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'  No  richer  gift  hath  Autumn  poured 
From  out  her  lavish  horn." 

The  Corn  Song — Whittier. 


FIELD  AND  LABORATORY 

STUDIES  OF  CROPS 


AN  ELEMENTARY  MANUAL 
FOR  STUDENTS  OF  AGRICULTURE 


BY 

A.    G.    McCALL 

Professar  of  Agronomy,  Ohio  State  University 


FIRST  EDITION 

FIRST  THOUSAND 


NEW  YORK 

JOHN  WILEY  &  SONS,  Inc. 
London:  CHAPMAN  &  HALL,  Limited 
1916 


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Copyright,  1916, 

BY 

A.  G.  McCALL 


THE  SCIENTIFIC  PRESS 

ROBERT  ORUMMOND  iVNO  COMPANY 

BROOKLYN.  N.  Y, 


SUGGESTIONS  TO  TEACHERS 


There  is  a  growing  tendency  in  the  schools  toward 
educating  children  in  the  common  things  of  life.  In  some 
States  laws  have  been  passed  requiring  the  teaching  of 
elementary  agriculture  in  the  village  and  rural  schools.  The 
object  of  this  work  is  to  interest  the  pupils  in  the  practical 
things  of  country  life  and  to  give  them  some  conception  of 
the  opportunities  which  surround  them.  A  majority  of 
the  children  who  attend  the  village  and  rural  schools  will 
remain  in  the  country,  and  it  is  right  and  proper  that  they 
should  be  educated  in  the  things  with  which  they  will  have 
to  deal  every  day  of  their  lives. 

The  success  of  the  work  will  depend  very  largely  upon  the 
teacher.  Pupils  are  naturally  interested  in  those  things 
with  which  they  are  constantly  in  contact,  and  need  only  the 
encouragement  of  the  teacher  to  direct  their  enthusiasm. 
In  this  manual  a  few  exercises  are  given  to  illustrate  some  of 
the  fundamental  principles  of  plant  growth,  but  the  central 
idea  throughout  is  the  practical  application  of  these  prin- 
ciples to  crop  production  and  improvement.  Some  of  the 
exercises  are  original,  but  many  of  them  have  been  adapted 
from  the  publications  of  the  United  States  Department  of 
Agriculture  and  from  the  bulletins  of  the  Extension  Depart- 
ment of  the  Ohio  State  University.  The  writer  wishes  to 
acknowledge  his  deep  indebtedness  to  his  wife,  Hattie  F. 
McCall,  for  helpful  criticisms  and  suggestions. 

355^28 


vi  SUaGESTIONS  TO  TEACHERS 

No  expensive  equipment  is  required,  but  every  effort 
should  be  made  to  induce  the  pupils  to  make  use  of  mate- 
rials on  the  home  farm  or  in  the  school  gardens.  Each  pupil 
should  have  at  home  or  in  the  school  garden  a  small  plot 
of  ground  on  which  to  grow  some  crops  for  which  he  shall 
be  entirely  responsible. 

The  book  is  expected  to  furnish  material  for  two  periods 
per  week  for  a  half  year  or  one  period  per  week  if  the  work  is 
extended  over  the  entire  school  term.  In  order  to  give 
the  teacher  some  choice  of  subjects,  fifty  exercises  have 
been  included.  They  are  arranged  in  logical  order,  but  it  is 
expected  that  this  arrangement  will  need  to  be  modified  in 
order  to  adapt  the  studies  to  the  season. 

In  addition  to  the  standard  books  on  elementary  agricul- 
ture, the  school  library  should  have  the  publications  of  the 
State  Experiment  Station,  the  Agricultural  College,  and 
the  United  States  Department  of  Agriculture.  The  former 
can  usually  be  obtained  by  direct  appUcation  to  the  Station 
and  College,  while  the  latter  can  be  secured  by  writing  to 
your  Senator  or  Representative  in  Congress.  The  Year- 
book and  the  Farmers'  Bulletins  are  the  most  useful  publica- 
tions put  out  by  the  federal  government. 

At  the  conclusion  of  each  exercise  the  pupils  should  be 
assigned  reference  readings  bearing  upon  the  work  of  the 
period  and  be  required  to  make  a  written  report.  As  far 
as  possible,  the  class-room  recitations  and  discussions  should 
center  about  the  field  and  laboratory  exercises. 

Department  of  Agronomy, 

Ohio  State  University, 

August,  1915. 


CONTENTS 


EXEKCISE  PAGE 

1 .  How  Plants  Grow 1 

2.  Where  The  Plant  Obtains  its  First  Food 3 

3.  To  Show  That  Plants  Get  Food  Material  from  the  Soil 5 

4.  To  Show  How  Plants  Take  up  Food  Material  from  the  Soil .  .  8 

5.  To  Show  That  Sunhght  is  Necessary  for  Plant  Growth 10 

o.  To  Show  That  Air  is  Necessary  for  the  Germination  of  Seeds 

and  the  Growth  of  Plants 12 

7.  To  Show  That  Heat  is  Necessary  for  Plant  Growth 14 

8.  To  Show  That  Plants  Take  up  Moisture  from  the  Soil  and 

Give  it  off  Through  their  Leaves 16 

9.  To  Show  the  Amount  of  Moisture  Retained  by  Plants 18 

10.  To  Study  the  Growth  Rate  of  Plants 20 

11.  To  Show  the  Proper  Depth  for  Planting 22 

12.  A  Study  of  Corn \ r4 

13.  The  Corn  Kernel 26 

14.  The  Study  of  an  Ear  of  Corn 29 

15.  Early  Growth  of  the  Corn  Plant 31 

16.  A  Study  of  the  Mature  Corn  Plant ^3 

17.  Pollination  of  Plants 26 

18.  The  Selection  of  Seed  Corn  in  the  Field 39 

19.  The  Storage  of  Seed  Corn 42 

20.  Judging  Corn  Ears 46 

21.  To  Study  the  Effect  of  Stand  upon  the  Yield  of  Corn 51 

22.  To  Test  the  VitaUty  of  Seed  Corn 53 

23.  Testing  the  Corn  Planter 57 

24.  To  Study  the  Necessity  for  Proper  Cultural  Methods  for  Corn.  59 

25.  The  Production  of  Corn  in  the  United  States 62 

26.  Study  of  a  Head  of  Wheat 65 

27.  Early  Development  of  the  Wheat  Plant 68 

28.  Judging  Wheat 70 

29.  The  Production  of  ^Vheat  in  the  United  State; 72 

vii 


viii  CONTENTS 

EXERCISE  PAGE 

30.  Early  Growth  of  the  Oat  Plant 74 

31.  Judging  Oats 76 

32.  The  Treatment  of  Seed  Oats  for  Smut 78 

33.  The  Production  of  Oats  in  the  United  States 80 

34.  Early  Growth  of  the  Rye  Plant 83 

35.  Early  Growth  of  the  Barley  Plant 84 

36.  The  Identification  of  Legume  Seeds 86 

37.  Purity  Test  for  Grass,  Clover  or  Alfalfa  Seed 88 

38.  A  Study  of  Weed  Seeds 92 

39.  Weed  Dissemination 94 

40.  A  Field  Study  of  Weeds 97 

41.  Germination  Test  for  Clover  or  Grass  Seed 101 

42.  A  Field  Study  of  Legumes 104 

43.  A  Study  of  Soy  Beans 106 

44.  A  Study  of  the  Potato 108 

45.  A  Field  Study  of  the  Potato Ill 

46.  Treatment  of  Seed  Potatoes  for  Scab 113 

47.  A  Laboratory  Study  of  Cotton 115 

48.  A  Study  of  Cotton  in  the  Field 118 

49.  A  Study  of  Rice 121 

50.  Planning  the  Home  Garden 122 

APPENDIX 

To  Observe  Corn  Day 129 


FIELD  AND  LABORATORY  STUDIES  OF  CROPS 


EXERCISE   1.     HOW  PLANTS    GROW 

Equipment:  Shallow  tray,  2X6X8  inches;  two  panes 
of  glass  about  5X8  inches;  a  spool  of  black  thread;  a 
strip  of  muslin  about  3  X 10  inches. 

Method:    Sprout  some  corn  kernels  in  a  germinator  or 


Fig.  1. — ^Arrangement  of  Tray  and  Glass  Plates  for  the  Study  of  Hoot 
Growth.     (U.  S.  Dept.  of  Agr.) 

between  the  folds  of  a  wet  cloth  until  the  roots  are  about 
two  to  three  inches  long.  Lay  one  piece  of  glass  in  the  tray, 
letting  one  end  rest  on  the  bottom  and  the  other  on  the 
opposite  edge  of  the  tray  as  shown  in  Fig.  1.  Wet  the 
strip  of  cloth  and  spread  it  on  the  pane  of  glass,  allowing 


2     fieijP  anxx  labqratory  studies  of  crops 

the  cloth  to  project  two  inches  beyond  the  upper  edge  of 
the  pane.  Lay  one  of  the  sprouted  grains  on  the  cloth  and 
tie  pieces  of  thread  around  the  roots  at  intervals  of  one- 
fourth  inch,  or^  if  waterproof  ink  is  available,  mark  the  roots 
with  a  fine  pen  instead  of  using  the  thread.  Now  place  the 
second  pane  of  glass  over  the  roots,  with  the  upper  edge  just 
below  the  seed,  placing  a  slender  piece  of  wood  between  the 
panes  to  prevent  crushing  the  plant.  Fold  the  corners  of 
the  cloth  about  the  seed,  put  water  into  the  pan  to  a  depth 
of  half  an  inch,  and  set  aside.  After  a  day  or  two  examine 
the  roots  and  note  where  the  lengthening  has  occurred. 

The  growth  of  the  stems  or  branches  of  plants  can  be 
studied  in  a  similar  manner  by  tying  pieces  of  thread 
around  them  at  intervals  of  one-fourth  inch,  or  by  marking 
them  with  ink.  Measure  carefully  from  time  to  time  the 
distance  between  the  top  mark  and  the  tip  of  the  plant,  to 
determine  whether  the  entire  stem  elongates  or  the  plant 
makes  its  growth  mainly  at  the  tip. 

Discussion :  This  exercise  shows  the  manner  in  which  the 
root  elongates  and  pushes  the  soft,  tender  tip  through  the 
soil.  Is  it  not  much  easier  for  the  roots  to  make  their  way 
through  a  fine,  mellow  seed  bed  than  through  a  hard  soil? 
How  necessary  it  is,  therefore,  to  have  the  soil  well  pulverized 
and  a  deep,  mellow  seed  bed  prepared  before  the  crop  is 
planted! 

Roots  follow  the  line  of  least  resistance,  and  if  the  sub- 
soil is  open  and  mellow  the  roots  will  penetrate  deeper 
than  they  otherwise  would,  thus  increasing  their  feeding 
zone.  If  the  soil  is  mellow  to  the  full  depth,  such  crops 
as  beets  and  carrots  will  develop  smooth,  well-shaped  roots. 


EXERCISE  2.     WHERE  THE  PLANT  OBTAINS  ITS  FIRST 

FOOD 

Equipment:  Two  small  tin  cans  filled  with  sandy  soil; 
a  few  beans;  some  grains  of  corn. 

Method:  (1)  Plant  two  beans  in  the  can  of  sandy 
soil  and  keep  the  soil  warm  and  moist.  As  soon  as  the 
leaves  appear  above  the  surface  of  the  soil,  carefully  remove 
the  two  half  beans,  or  cotyledons,  from  one  of  the  plants 
with  a  sharp  knife.  Compare  for  a  week  the  develop- 
ment of  the  two  plants  and  note  the  more  rapid  growth 
of  the  plant  from  which  the  cotyledons  have  not  been 
removed. 

(2)  Select  four  grains  of  corn  and  pare  off  from  two 
of  them  the  starchy  outer  part  (endosperm),  with  a  sharp 
knife,  leaving  only  the  germ.  Plant  these  germs  and  the 
two  entire  grains  in  a  can  of  sandy  soil  and  compare  the 
growth  and  development  of  the  plants. 

Discussion:  The  young  plant  gets  its  first  food  from 
the  supply  of  material  which  is  stored  in  the  seed,  tuber, 
or  other  part  which  is  planted.  This  stored  material 
should  be  sufficient  in  amount  to  supply  the  young  plant 
until  it  can  send  roots  out  into  the  soil  to  secure  water, 
which   carries   food   materials  in   solution,  and  its  leaves 

3 


4      FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

have  forced  their  way  to  the  surface  wliere  they  may  absorb 
carbon  dioxide  from  the  air. 


Fig.  2. — Beans  Planted  the  Same  Day,  but  the  Plant  to  the  Left  was 
Deprived  of  its  Food  Supply  by  the  Removal  of  the  two  Half  Beans 
or  Cotyledons.     (After  Graham.) 


EXERCISE   3.     TO    SHOW   THAT   PLANTS    GET   FOOD 
MATERIAL   FROM   THE    SOIL 

Equipment:  Two  quarts  of  clean  sand;  two  flower  pots 
or  quart  cans;  a  few  beans. 

Method :  Heat  the  sand  to  redness  on  a  shovel  or  in  an 
iron  pan  until  all  the  organic  matter  is  burned  out.  Fill  the 
two  pots  with  this  ignited  sand.  Select  ten  large,  plump 
beans  and,  after  soaking  them  over  night,  plant  five  in  each 
pot.  Water  both  pots  with  rain-  or  distilled  water  and  set 
them  in  a  warm  place  until  the  beans  begin  to  grow.  After 
this,  treat  both  pots  alike,  except  that  one  is  watered  with 
rain-water  and  the  other  is  supplied  with  a  soil  solution.* 
As  soon  as  the  beans  are  about  two  inches  high,  thin  out, 
leaving  three  uniform  plants  in  each  pot. 

Continue  the  watering  until  the  plants  are  four  of  five 
weeks  old,  by  which  time  the  beans  that  have  received  the 
soil  solution  should  be  much  larger  and  stronger  than  those 
that  have  received  only  rain-water.  To  what  is  this  differ- 
ence in  growth  rate  due?  Why  not  use  spring-water  instead 
of  rain-water? 

Discussion :  Plant  food  in  the  soil  is  dissolved  by  water 
and  by  weak  acids  given  off  by  the  root  hairs  much  in  the 

*  To  make  this  soil  solution  fill  a  large  pail  half  full  with  rich  soil 
from  beneath  or  near  the  edge  of  a  manure  heap  and  add  enough  rain- 
water to  fill  the  pail.  Stir  and  set  aside  to  settle,  then  strain  off  some  of 
the  liquid  through  a  piece  of  cheesecloth. 

5 


6      FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

same  way  that  sugar  and  salt  are  dissolved.     In  this  condi- 
tion plant  food  can  be  taken  in  by  the  roots  as  easily  as  pure 


Fig.  3. — The  Roots  of  the  Corn  Plant  Absorb  Food  Materials  from  the 
the  Soil  to  the  Depth  of  Three  Feet  or  More. 

water.    We  think  of  the  "  clear-as-crystal  "  well-water  that 
we  drink  as  being  pure  water,  but  we  know  that  often  it 


PLANTS  GET  FOOD  MATERIAL  FROM  THE  SOIL    7 

contains  so  much  lime  that  every  few  weeks  we  have  to  chip 
off  the  scale  of  lime  on  the  inside  of  the  teakettle. 

Well-water  may  also  contain  other  substances  in  solution. 
Suppose  you  try  an  experiment  to  show  this  by  fastening 
sprouted  kernels  of  wheat  on  thin  slices  of  floating  cork  in 
such  manner  that  the  roots  will  hang  over  the  edges  of  the 
cork  down  into  the  water.  Put  some  of  the  seedlings  thus 
arranged  into  a  tumbler  of  clean  rain-water  and  others  into 
a  tumbler  of  clean  well-water  and  watch  their  development. 

A  study  of  the  chemical  composition  of  plants  reveals 
the  fact  that  the  greater  part  of  the  dry  matter  of  the 
plant  is  derived  from  the  air.  But  before  it  can  utilize 
the  elements  from  the  air,  the  plant  must  be  able  to  take 
up  certain  mineral  substances  from  the  soil. 

In  ten  pounds  of  mature  corn  plant  there  will  be  found 
approximately  eight  pounds  of  water  and  two  pounds  of 
dry  material,  of  which  two  ounces  have  been  taken  up 
from  the  soil,  the  remainder  coming  from  the  air. 


EXERCISE  4.     TO  SHOW  HOW  PLANTS  TAKE  UP  FOOD 
MATERIAL   FROM   THE    SOIL 


Equipment:  Small  glass  tube  or  funnel  with  a  long 
stem;  a  piece  of  bladder  or  parchment  paper;  some  sugar 
or  molasses;  a  glass  can,  or  wide-mouthed  bottle. 

Method:  Soak  the  bladder  or 
parchment  in  water  until  soft,  stretch 
the  membrane  over  the  end  of  the 
funnel  and  hold  it  securely  by  wrap- 
ping tightly  with  waxed  thread.  Now 
fill  the  funnel  with  a  strong  sugar 
solution  or  with  molasses,  until  the 
liquid  stands  about  one  inch  in  the 
stem.  Partly  fill  the  jar  with  water 
and  insert  the  funnel  until  the  water 
on  the  outside  is  at  the  same  level  as 
the  molasses  or  sugar  solution  on  the 
inside  of  the  funnel.  In  a  short  time 
the  solution  in  the  funnel  will  be 
seen  to  rise  above  the  level  of  the 
water  in  the  jar  and  after  a  time 
overflow  at  the  top  if  the  stem  of  the 
funnel  is  not  too  long. 
Discussion:  This  increase  in  the  volume  of  molasses 
or  sugar  solution  is  due  to  the  entrance  of  water  through 
the   bladder  or   parchment  membrane.     There   is  a  slow 

8 


Fig.  4.  —  Arrangement 
of  a  Bladder  Mem- 
brane to  Show  How 
Plants  Take  up  Food 
Material. 


HOW  PLANTS  TAKE  UP  FOOD  MATERIAL    9 

movement  in  the  opposite  direction,  but  since  the  water 
moves  through  the  membrane  much  more  rapidly  than 
the  molasses  or  sugar,  there  is  a  rapid  increase  in  the 
volume  of  liquid  on  the  inside  of  the  funnel.  This  move- 
ment through  the  membrane  will  continue  until  the  solu- 
tion on  the  inside  has  the  same  strength  or  concentration 
as  that  on  the  outside.  The  exchange  of  liquids  through 
membranes  is  called  osmosis.  By  this  process  the  fine 
root  hairs  of  the  plant  are  able  to  secure  a  large  amount 
of  water  from  the  moist  soil.  The  thin  wall  of  the  root 
hair  corresponds  to  the  bladder  or  parchment  membrane, 
the  cell  sap  to  the  sugar  solution,  and  the  soil  moisture 
to  the  water  in  the  jar.  The  sap  is  more  concentrated 
than  the  soil  solution  on  the  outside  of  the  hair,  hence  the 
water  in  the  soil  moves  through  the  cell  wall  just  as  the 
water  in  the  jar  moved  through  the  membrane  and  into 
the  sugar  solution. 

Sprout  some  grains  of  corn  and  wheat  between  layers 
of  dark  flannel  and  note  the  very  fine  hairs  which  develop 
just  back  of  the  growing  root  tip.  The  moisture  which 
enters  the  plant  through  the  root  hairs  carries  in  solution 
certain  food  materials  which  are  essential  for  the  develop- 
ment of  the  plant.  The  moisture  passes  up  through  the 
plant  and  much  of  it  is  evaporated  from  the  leaves  after 
having  performed  its  functions  as  a  carrier  of  food  materials 
from  the  soil  through  the  plant  to  the  leaf.  The  food 
materials  carried  by  the  water  are  left  behind  in  the  leaf 
where  they  are  combined  with  substances  from  the  air  to 
form  the  tissue  of  the  plant,  including  roots,  stems,  leaves, 
and  seeds. 


EXERCISE  5.     TO  SHOW  THAT  SUNLIGHT  IS  NECES- 
SARY FOR  PLANT   GROWTH 

Equipment:  Two  flower  pots;  some  grains  of  wheat 
and  corn. 

Method:  Fill  the  two  pots  with  moist  soil  and  plant 
to  wheat  or  corn.  Place  one  of  the  pots  in  the  window  and 
cover  the  other  with  a  black  paper  cone  or  a  box  through 
which  the  light  cannot  penetrate.  Give  both  pots  the  same 
temperature  and  the  same  moisture  supply.  Observe  the 
contrast  in  the  appearance  of  the  two  sets  of  plants.  After 
the  plants  under  the  cone  or  box  have  reached  a  height  of 
three  or  four  inches,  remove  the  covering  and  note  what 
takes  place. 

Discussion :  The  leaves  are  the  workshop  of  the  plant. 
It  is  here,  under  the  influence  of  sunshine,  that  the  plant 
takes  the  food  materials  from  the  air  and  combines  them 
with  the  nutrients  gathered  from  the  soil  by  the  roots. 
The  process  which  goes  on  in  the  leaf  results  in  the  pro- 
duction of  the  starches,  sugars,  fats  and  proteid  substances 
which  are  stored  in  the  body  and  seeds  of  the  plant.  The 
details  of  the  process  are  not  understood,  but  we  know  that 
sunlight  is  a  necessary  factor. 

The  work  of  the  green  leaves  of  the  plant  is,  therefore, 
to  manufacture  sugar  and  starches,  which  are  sometimes 
called  carbohydrates.  This  is  an  extremely  important  proc- 
ess, for  all  life  on  the  earth  is  dependent  upon  it  for  support. 

10 


SUNLIGHT  NECESSAEY  FOR  PLANT  GROWTH     11 

Plants  must  manufacture  carbohydrates  not  only  for  their 
own  use,  but  also  for  the  use  of  animals.     This  process 
cannot  go  on  unless  the  leaves  are  exposed  to  the  light. 
The  name  photosynthesis,  which  is  given  to  this  process, 
means  that  the  work  is  done  in  the  presence  of  light.     In 
the  manufacture  of  carbohydrates  the  leaves  use  as  raw 
materials  two  substances  which  are  very  common  in  nature 
and  easily  obtained  by  the  plant.     One  of  these  substances 
is  water,  which  the  plant  roots  absorb  from  the  soil  while 
the  other  is  carbon  dioxide,  a  gas  which  is  present  in  small 
quantities  in  the  air  but  which  is  constantly  being  renewed, 
so  that  there  is  always  an  abundance.     Water  is  made  up 
of  one  part  of  oxygen  and  two  parts  of  hydrogen,  while 
carbon  dioxide  consists  of  one  part  of  carbon  and  two 
parts  of   oxygen.     These  are  the  elements  that  enter  into 
the  composition    of    a    carbohydrate.      In   this   photosyn- 
thetic  process  the  elements  of  the  water  and  the  carbon 
dioxide  are  separated  and  in  the  presence  of  light  are  re- 
combined    to    form    carbohydrates.     During    this    process 
oxygen  is  given   off  from  the  leaf  as  a  waste   product. 
Therefore,  in  the  sunlight  the  leaf  is  constantly  taking  in 
carbon  dioxide  and  giving  off  oxygen.    If  an  actively  growing 
water-plant  is  submerged  in  a  glass  of  water  and  exposed 
to  bright  light,  bubbles  of  oxygen  may  be  seen  coming 
from   the  plant  and   rising  to  the  surface.     Shading  the 
glass  diminishes  the  rate  at  which  the  bubbles  appear. 


EXERCISE  6.  TO  SHOW  THAT  AIR  IS  NECESSARY  FOR 
THE  GERMINATION  OF  SEEDS  AND  THE  GROWTH 
OF   PLANTS 

Equipment:  Two  tumblers  or  quart  cans;  several 
grains  of  corn. 

Method:  Fill  two  tumblers  within  a  half  inch  of  the 
top  with  rich  soil.     Plant  in  each  three  kernels  of  corn. 


Fig.  5. — The  Seed  Planted  in  the  Tumbler  to  the  right,  Rotted  because 
it  was  Deprived  of  Air  by  the  Excess  of  Moisture  in  the  Soil. 


Water  tumbler  No.  1  only  enough  each  day  to  keep  the  soil 
moist.  Keep  water  in  the  second  tumbler  so  that  it  stands 
a  little  above  the  surface  of  the  soil.  The  seeds  in  the  first 
tumbler  will  undoubtedly  germinate  in  a  short  time,  while 

12 


AIR  NECESSARY  FOR  SEEDS  AND  PLANTS         13 

the  seeds  in  the  other  tumbler  will  require  a  longer  time  to 
germinate,  and,  if  the  temperature  of  the  room  in  which  the 
two  glasses  are  kept  is  low,  the  seeds  will  rot.  The  tumbler 
which  contains  an  excessive  amount  of  moisture  prevents 
the  access  of  air  that  is  necessary  to  the  germination  of  the 
seed,  while  the  one  which  is  kept  only  moderately  moist 
allows  a  sufficient  amount  of  air  to  come  in  contact  with 
the  seeds  to  insure  germination. 

Discussion :  For  the  best  growth  of  crops  the  space  not 
occupied  by  soil  particles  should  be  divided  equally  between 
air  and  water.  If  this  space  becomes  entirely  filled  with 
water,  crops  will  not  thrive,  since  their  roots  will  not  be 
able  to  get  the  air  necessary  for  plant  growth.  Some  plants, 
such  as  the  cypress  and  the  water  lily,  have  special  structures 
which  enable  them  to  obtain  air  from  the  water  while  their 
roots  are  entirely  submerged,  but  our  common  field  plants 
do  not  have  this  ability. 

Of  the  various  means  employed  to  improve  land  that  is 
naturally  unfit  for  cultivation,  there  is  none  which  exceeds 
in  importance  the  operation  of  tile  drainage.  A  large  part 
of  the  United  States  is  well  drained  naturally  because  of 
the  open  structure  of  the  subsoil,  which  permits  the  surplus 
water  to  pass  away  rapidly  into  the  underground  channels 
and  from  thence  into  the  small  streams  and  rivers.  In 
many  cases,  however,  the  subsoil  is  too  tight  and  compact 
to  allow  free  percolation  of  the  water  and  artificial  drain- 
age is  needed. 


EXERCISE  7.     TO   SHOW  THAT  HEAT  IS  NECESSARY 
FOR   PLANT   GROWTH 

Equipment:  Two  flower  pots  or  tin  cans  and  a  few 
grains  of  corn  or  wheat. 

Method:  Fill  the  pots  with  soil  and  plant  the  same 
number  of  seeds  in  each.  The  pots  should  be  watered 
and  treated  exactly  alike  except  that  one  is  kept  at  room 
temperature  (65°  to  85°  F.),  while  the  other  pot  is  kept 
in  a  cool  place  at  a  temperature  of  40°  to  50°  F.  Note 
the  time  necessary  for  the  plants  to  appear  above  the  sur- 
face of  the  soil  and  the  rate  at  which  growth  takes  place. 


Date  of 
Planting. 

Date  up 

Average  Height  of  Plants, 

2d  day. 

4th  day. 

6th  day. 

Room  tempera- 
ture 

Low    tempera- 
ture   

Discussion:  Some  seeds  will  germinate  at  a  tempera- 
ture only  slightly  above  freezing,  while  others  require  a 
much  higher  temperature.  Oats,  clover  and  other  crops 
that  are  seeded  early  in  the  spring  have  seeds  that  germinate 
at  a  comparatively  low  temperature,  while  corn  and  melons 
must  not  be  planted  until  the  soil  has  attained  a  much 
higher  temperature. 

14 


HEAT  IS  NECESSARY  FOR  PLANT  GROWTH       15 


TEMPERATURES   FOR  GERMINATION 


Crop. 

Lowest  Temperature, 
Deg.  F. 

Best  Temperature, 
Deg.  F. 

Wheat 

32-40 
32-40 
45-50 
60-65 

77-88 

Oats     

77-88 

Corn 

90-92 

Melons.       

88-99 

A  low  temperature  frequently  retards  germination  to 
such  an  extent  that  the  seed  rots  without  producing  a 
plant.  Thorough  drainage  and  proper  cultural  methods 
help  the  soil  to  warm  up  promptly  and  afford  conditions 
favorable  for  quick  germination  and  rapid  growth  of  the 
young  plants. 


EXERCISE  8.  TO  SHOW  THAT  PLANTS  TAKE  UP 
MOISTURE  FROM  THE  SOIL  AND  GIVE  IT  OFF 
THROUGH   THEIR   LEAVES 


Equipment :    Small 


Fig.  6.— When  this  Plant 
is  Placed  in  a  Sunny 
Window,  Drops  of 
Water  soon  Collect  on 
the  Inside  of  the  Glass 
Can. 


potted  plant;  wide-mouthed  jar; 
piece  of  cardboard,  6X6  inches; 
wax. 

Method :  Use  a  plant  which  is 
at  least  three  or  four  inches  high 
and  growing  in  a  flower  pot  or  to- 
mato can.  Cut  a  slit  in  the  card- 
board from  the  middle  of  one  side 
to  the  center  and  place  it  around 
the  plant.  Seal  up  the  slit  in  the 
cardboard  with  any  soft  wax.  In 
place  of  the  cardboard,  the  surface 
of  the  soil  may  be  sealed  over 
with  melted  paraffin  or  with  model- 
ing clay.  The  object  of  the  seal  is 
to  prevent  the  water  from  evapor- 
ating directly  from  the  surface  of 
the  soil  and  condensing  on  the 
inside  of  the  jar.  Now  invert  the 
glass  jar  over  the  plant  and  place 
in  a  sunny  window.  How  do  the 
drops  of  water  get  into  the  glass 
jar? 


Discussion: 
16 


Plants    are    con- 


PLANTS  TAKE  UP  MOISTURE  FROM  THE  SOIL     17 

stantly  giving  off  water  from  their  leaves.  The  largest 
amount  is  evaporated  in  the  hot  sun  and  when  an  abun- 
dance of  water  is  suppHed  to  the  roots.  Sometimes  in  a 
drouth  more  water  is  evaporated  from  the  leaves  than  is 
being  taken  in  by  the  roots.  If  this  is  continued  for  some 
time,  the  plant  wilts.  This  reminds  us  that  the  water  in 
plants  gives  the  soft  stems  and  leaves  their  stiffness.  All 
the  food  which  the  plant  takes  from  the  soil  must  first  be 
dissolved  in  water.  It  is  estimated  that  900  tons  of  water 
are  evaporated  by  each  acre  of  corn  plants  during  the  grow- 
ing season. 

In  many  seasons  water  is  undoubtedly  the  limiting  factor 
in  corn  production.  It  has  been  found  that  the  total  yields 
of  com  for  the  corn  belt  may  be  predicted  from  the  rainfall 
during  the  month  of  July.  It  has  been  found  that  in  an 
average  season  an  additional  inch  of  rainfall  retained  in  the 
soil  during  July  means  an  increase  of  $5,000,000  in  the  value 
of  the  com  crop  in  a  single  state. 

Unfortunately,  rain  does  not  always  fall  when  it  is  most 
needed,  but  by  proper  tillage  and  cultivation,  large  quan- 
tities of  moisture  may  be  conserved  until  July. 


EXERCISE  9.     TO  SHOW  THE  AMOUNT  OF  MOISTURE 
RETAINED   BY   PLANTS 

Equipment :    A  pair  of  scales  and  a  drying  oven. 

Method;  Dig  up  enough  clover  or  corn  plants  from 
the  field  to  weigh  about  five  pounds.  (If  accurate  balances 
are  available  a  single  plant  will  be  sufficient.)  Weigh 
carefuU}^  and  record  the  weight.  Place  the  material  in 
a  shallow  tray  or  pan,  set  the  pan  in  bright  sunlight  until 
the  contents  are  thoroughly  dry  and  again  weigh.  Sub- 
tract this  weight  from  the  original  weight  and  calculate 
the  per  cent  of  moisture  lost. 

How  many  pounds  of  green  clover  are  necessary  to 
make  a  ton  of  cured  hay?  How  much  dry  corn  fodder 
in  a  ton  of  green  corn  plants? 

Place  the  dried  plants  in  a  drying  oven  and  see  if  more 
water  can  be  driven  off. 


Kind  of  Plant. 


Green  Weight. 


Sun-dried. 


Oven-dried. 


Per  cent  of 

Moisture  in 

the  Green 

Plants. 


18 


AMOUNT  OF  MOISTURE  RETAINED  BY  PLANTS     19 

Discussion:  We  have  already  found  that  a  large  part 
of  the  water  taken  up  by  the  roots  is  evaporated  from  the 
leaves  of  the  plant,  leaving  behind  tne  food  material  which 
it  carried  in  solution  from  the  soil.  We  now  see  that  a 
sufficient  amount  of  water  is  retained  to  make  up  a  large 
percentage  of  the  total  green  weight  of  the  plant.  This 
moisture  gives  rigidity  to  the  plant.  When  the  loss  by 
evaporation  from  the  leaf  surface  is  more  rapid  than  the 
water  can  be  supplied  from  the  soil,  the  plant  soon  wilts 
and  ceases  to  grow.  It  has  been  found  that  our  ordinary 
plants  take  up  from  300  to  500  pounds  of  water  for  every 
pound  of  dry  matter  produced  by  them. 

From  an  experiment  in  New  York  State  it  was  found 
that  a  field  of  oats  used  522  pounds  of  water  for  each  pound 
of  dry  matter  produced;  corn  234  pounds;  and  potatoes 
423  pounds. 

The  evaporation  of  the  water  from  the  surface  of  the 
leaf  is  known  as  transpiration. 

In  addition  to  the  large  amount  of  water  which  leaves 
the  soil  through  the  plant,  there  is  a  constant  loss  of  water 
by  direct  evaporation  from  the  surface  of  the  soil. 


EXERCISE  10.  TO  STUDY  THE  GROWTH  RATE  OF 

PLANTS 

Equipment;  A  home-made  measuring  device  similar  to 
the  one  shown  in  Fig.  7;  a  corn  or  bean  seedUng  growing 
in  a  pot  or  tumbler. 


Fig.  7.' — A  Simple  Device  for  Measuring  the  Growth  Rate  of  Plants. 

Method :  By  means  of  a  light  cord  attach  the  tip  of  the 
leaf  or  the  end  of  a  growing  stem  to  the  short  end  of  the  light 
lever  arm  as  shown  in  the  drawing.  Since  the  lever  arm  to 
the  right  is  eight  times  as  long  as  the  end  attached  to  the 
plant,  an  elongation  of  one  inch  in  the  plant  will  permit  the 
long  end  of  the  pointer  to  drop  a  distance  of  eight  inches  on 

20 


THE  GROWTH  RATE  OF  PLANTS  21 

the  scale.  Remove  the  plant  from  a  warm  to  a  cold  room  and 
compare  the  growth  rates.  Compare  the  growth  rate  at 
night  with  that  of  the  same  plant  in  sunlight. 

Water  the  plants  in  one  pot  with  liquid  manure,  and 
those  in  another  with  water  to  which  has  been  added  a 
spoonful  of  ammonia.  For  a  third  pot  use  water  to  which 
has  been  added  a  spoonful  of  commercial  fertilizer.  Com- 
pare the  growth  rates  of  the  plants  under  the  different 
treatments. 

Discussion:  Some  plants  make  very  rapid  growth  and 
mature  a  crop  in  a  few  weeks  or  months,  while  others  require 
a  long  growing  period.  The  growth  rate  of  plants  in  the 
field  or  garden  depends  not  only  upon  the  kind  of  plant,  but 
also  upon  the  temperature  of  the  soil,  the  sunshine,  and  the 
abundance  of  plant  nutrients  in  the  soil. 

Soils  that  have  a  sandy  texture  warm  up  more  promptly 
in  the  spring  than  heavy  clay  soils  because  they  contain 
less  moisture.  For  this  reason  soils  of  a  sandy  nature  should 
be  chosen  for  the  growing  of  early  truck  crops  and  garden 
vegetables. 

Manures  and  fertilizers  applied  to  field  and  garden 
crops  increase  their  growth  rate  by  furnishing  food  mate- 
rials for  the  immediate  use  of  the  plants. 


EXERCISE    11.      TO   SHOW  THE  PROPER  DEPTH  FOR 
PLANTING 

Equipment:  A  case  consisting  of  two  panes  of  glass 
placed  about  one-half  inch  apart  and  held  in  position  by 
means  of  a  wooden  frame. 

Method :  Put  an  inch  or  two  of  soil  in  the  bottom  of  the 
glass  case  and  then  place  a  kernel  of  corn  on  top  of  the  soil 
close  up  to  the  glass.  At  the  other  end  of  the  case  a  bean 
may  be  planted  in  the  same  manner.  Now  put  in  an  inch 
of  soil  and  again  plant  a  kernel  of  corn  and  a  bean,  con- 
tinuing the  operation  until  the  case  is  full  of  soil  to  within 
an  inch  of  the  top.  Water  the  soil  thoroughly,  cover  the  glass 
sides  with  black  cloth  or  paper  to  exclude  the  light  and  set 
the  case  aside  until  the  seeds  have  germinated.  Other  seeds 
than  corn  and  beans  may  be  included  in  the  exercise. 

Discussion :  Seeds  which  are  small  and  fine  must  not  be 
deeply  covered  with  earth,  for,  if  they  are,  the  weak  germ 
which  they  contain  will  not  be  strong  enough  to  reach  the 
light  and  air.  Large  seeds,  however,  which  contain  a  con- 
siderable quantity  of  stored  material,  as  in  the  case  of  peas 
and  beans,  may  be  planted  quite  deeply.  In  fact,  peas, 
which  do  not  force  the  seed  leaves  out  of  the  ground,  should, 
for  best  results,  be  planted  from  three  to  five  inches  in  depth, 
while  beans,  which  have  a  different  method  of  germination, 
forcing  their  seed  leaves  out  of  the  ground,  should  not  be 
planted  too  deeply,  for,  as  in  the  case  of  soils  which  are  clayey 

22 


THE  PROPER  DEPTH  FOR  PLANTING 


23 


and  compact  in  nature,  there  will  not  be  sufficient  power  in 
the  growing  stem  of  the  bean  to  force  the  seed  leaf  from 


Fig.  8. — ^A  Glass  Case  to  Show  the  Results  of  Deep  and  Shallow  Plant- 
ing.    (U.  S.  Dept.  of  Agriculture.) 

the  soil  and  out  into  the  light.  The  depth  of  planting, 
therefore,  must  be  regulated  by  the  habit  of  growth  of  the 
plant. 


EXERCISE    12.     A   STUDY   OF   CORN 

Equipment:  Samples  of  dent,  flint,  pop  and  sweet 
corn  and  a  copy  of  the  last  census  report  or  the  Yearbook 
of  the  United  States  Department  of  Agriculture. 

Method:  Study  the  points  of  difference  between  these 
different  types  of  corn  by  examining  their  exterior  and  by 
cutting  the  grains  in  sections.  What  is  each  kind  used  for? 
What  kind  is  grown  in  your  district?  From  the  census 
reports,  find  the  states  which  produce  the  greatest  amount 
of  corn.  How  does  the  value  of  the  corn  crop  in  your  state 
compare  with  that  of  wheat  and  oats?  Where  is  flint  corn 
grown?  By  inquiry  find  out  how  many  acres  of  corn  are 
grown  on  four  different  farms  in  your  neighborhood  and  also 
the  yield  per  acre.  Compute  the  value  per  acre  at  the  regu- 
lar market  price  and  fill  out  the  following  table : 


Total         i     Yield  per 

! 

Total 
production 

Value  per 
acre 

Fir.st  farm 

Second  farm 

Third  farm 

Fourth  farm      | 

Have  the  pupils  each  bring  ten  ears  of  the  best  corn  they  can 
find  at  home,  for  use  in  the  exercise  on  corn  judging. 

24 


A  STUDY  OF  CORN  25 

Discussion :  On  some  of  the  farms  of  your  neighborhood 
the  yields  are  low  because  the  soil  needs  drainage,  while  on 
others  the  soil  is  in  need  of  manures  and  fertilizers.  But 
rich,  well-drained  soil  sometimes  fails  to  produce  good 
crops  because  poor  seed  is  used  or  the  seed  bed  is  improperly 
prepared. 

Both  the  dent  and  the  flint  types  of  corn  are  grown 
extensively  in  the  United  States.  Flint  corn  is  confined 
principally  to  the  New  England  States,  New  York,  Canada 
and  regions  of  similar  climatic  conditions.  Further  south, 
throughout  the  central  part  of  the  United  States,  the  dent 
type  is  grown  almost  exclusively;  it  has  a  longer  growing 
period  than  the  flint  corn  and  produces  larger  yields. 

For  the  best  results  corn  should  be  planted  in  rich, 
mellow,  well-drained  loam  soil  and  given  thorough  and 
frequent  shallow  cultivation  throughout  the  growing  season. 


EXERCISE  13.  THE  CORN  KERNEL 

Equipment:  Samples  of  white,  yellow  and  red  corn; 
a  shallow  pan. 

Method:  Soak  the  kernels  from  white,  yellow  and  red 
ears  over  night  in  water.     Supply  each  student  with  a  num- 


— Graiu  Cap 
Fig.  9. — Diagram  Showing  the  Parts  of  a  Grain  of  Corn. 

ber  of  grains  of  each  different  color,  both  soaked  and  dry. 
After  drawing  an  exterior  view  showing  the  groove  side^ 
the  grains  should  be  cut  in  sections,  and  drawings  made  of 
cross-  and  longitudinal  sections.  The  drawings  should  show 
the  difference  in  structure  of  the  different  parts  of  the  grain. 

26 


THE  CORN  KERNEL 


27 


^* 


Fig.  10. — External  and  Sectional  Views  of  a  Grain  of  Corn. 


Fig.  11. — Enlarged  Photograph  of  Sprouting  Grains.     The  Stem  above 
and  the  Roots  Growing  downward.     (Extension  Department.) 


28     FIELD  AND  LABORATOKY  STUDIES  OF  CROPS 

Remove  the  outer  covering  from  some  of  the  soaked 
grains  and  observe  the  location  of  the  color.  Where  is  the 
white  color  located  in  the  white  grains?  What  is  the  color 
of  the  hull  of  the  yellow  grain?  The  color  of  the  endosperm? 
.  What  is  the  color  of  the  red  grains  after  the  hull  has  been 
removed? 

Discussion:  The  corn  kernel  is  composed  of  four  dis- 
tinct parts:  (1)  the  hull,  which  ig  the  thin,  outer  layer  which 
covers  the  entire  grain,  (2)  the  aleurone  layer,  which  is  very 
thin  and  located  just  under  the  hull,  (3)  the  endosperm,  which 
occupies  about  three-fourths  of  the  entire  grain  and  (4)  the 
embryo,  or  germ,  which  is  the  hving  part  of  the  grain. 

The  endosperm  is  composed  very  largely  of  starch,  and 
furnishes  the  food ,  for  the  young  plant  after  germination 
and  until  it  has  gotten  its  roots  into  contact  with  the  soil 
and  its  leaves  exposed  to  the  air.  The  endosperm  is 
made  up  of  two  kinds  of  material,  one  white  and  starchy 
and  the  other  hard  and  horny.  The  embryo  is  embedded 
in  the  endosperm  just  under  the  groove  which  occupies 
one  side  of  the  grain.  The  little  plant  which  is  snugly 
folded  into  the  cavity  can  be  seen  with  the  naked  eye  after 
the  surface  of  the  grain  is  cut  away  with  a  sharp  knife. 
When  the  grain  is  planted  in  the  soil,  it  absorbs  moisture 
and,  if  temperature  conditions  are  favorable,  the  little  plant 
pushes  its  roots  out  into  the  soil,  and  extends  its  leaves  up 
into  the  air. 


EXERCISE  14.  THE  STUDY  OF  AN  EAR  OF  CORN 

Equipment:  Ten-ear  samples  of  different  varieties  of 
corn;  tape  line;  a  pair  of  postal  scales  or  a  torsion  balance. 

Method:  Having  supplied  each  student  with  a  ten-ear 
sample,  the  work  should  proceed  as  follows:  (1)  Number 
the  individual  ears  of  each  sample  on  a  small  tab  attached 
to  the  butt  of  the  ear  by  means  of  a  small  nail. 


Ear 
No. 

Length. 

Circumfer- 
ence. 

Weight. 

Number 

of 

rowa. 

Number  of 
kernels 
per  row. 

Number  of 
kernels 
per  ear. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

Average 

29 


30    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 


(2)  Weigh  and  measure  each  ear,  recording  the  weight  in 
ounces  or  grams  and  the  length  and  circumference  in  inches 
and  fractions  of  an  inch. 

(3)  Record  the  number  or  rows  of  kernels  and  the  num- 
ber of  kernels  per  row  and  the  total  number  of  kernels  per 
ear. 

(4)  Select  two  representative  ears  from  each  sample, 
shell,  and  determine  the  per  cent  of  shelled  corn. 


Ear  Number. 

Total 
Weight  of  ear. 

Weight 
Shelled  corn. 

Per  cent  of 
Shelled  corn. 

Are  the  large  ears  always  the  heaviest?  Why  is  there 
always  an  even  number  of  rows?  Can  you  see  any  relation 
between  the  width  of  the  grains  and  the  number  of  rows  on 
the  cob?  How  many  ears  of  the  average  size  will  be  required 
to  make  a  70-pound  bushel?  From  your  shelling  test  cal- 
culate how  many  ears  are  required  to  make  a  56-pound  bushel 
of  shelled  corn.  How  many  bushels  of  shelled  corn  in  100 
bushels  of  ear  corn  which  averages  75  per  cent  of  shelled 
corn?     85  per  cent  of  shelled  corn? 

Discussion :  A  great  variation  is  found  in  the  size,  weight 
and  shape  of  the  ears  of  different  varieties  of  corn  and  also 
in  the  individual  ears  of  a  particular  variety.  Ears  with 
medium-size  cob  and  deep  grains  are  much  more  valuable 
for  feeding  purposes  than  those  with  shallow  grains  and  large 
cobs. 


EXERCISE  15.     EARLY  GROWTH  OF  THE  CORN  PLANT 

Equipment :  Preparation  for  this  exercise  must  be  made 
four  weeks  in  advance,  by  planting  two  small  plots  of  corn, 
one  at  the  depth  of  one  inch  and  the  other  three  inches  deep. 
Repeat  this  planting  each  week,  in  order  to  have,  for  the 
exercise,  plants  one  week  old  and  others  that  have  reached 
the  ages  of  two,  three  and  four  weeks.  The  plantings  may 
be  made  in  soil,  but  the  plants  will  be  much  more  easily 
handled  if  grown  in  boxes  of  sand,  since  the  sand  will  wash 
off  the  roots  much  more  readily  than  soil. 

Method:  Dig  up  a  sufficient  number  of  plants  and  care- 
fully wash  the  sand  away  without  injuring  the  roots.  Ex- 
amine the  root  systems  of  the  plants  of  different  ages  and 
compare  those  planted  at  different  depths.  Make  draw- 
ings of  the  entire  plants  at  different  stages  of  their  develop- 
ment and  show  the  three  temporary  roots  which  develop 
first  and  also  the  permanent  roots  which  make  their  appear- 
ance later  at  one  of  the  joints  or  nodes  situated  about  one 
inch  below  the  soil  surface. 

Discussion :  The  roots  of  the  corn  plant  may  be  divided 
into  three  groups:  (1)  temporary,  (2)  permanent  feeding 
roots,  and  (3)  brace  roots.  When  the  kernel  of  corn  germi- 
nates, it  sends  down  into  the  soil  a  shoot  from  which  two  or 
three  lateral  branch  roots  develop.  These  roots  with  their 
branches  form  the  temporary  root  system  and  supply  the 

31 


32     FIELD  AND  LABOKATORY  STUDIES  OF  CROPS 


young  plant  with  moisture.     During  the  early  growth  stage 

the  young  plant  is  nourished  by  the  food  which  is  stored  up  in 

the  kernel,  but  by  the  time 
the  plants  appear  above  the 
ground  a  permanent  root 
system  has  begun  to  form 
about  an  inch  below  the 
surface  of  the  ground.  This 
system  grows  very  rapidly 
at  first  and  by  the  time  the 
plants  are  a  month  old  the 
roots  will  meet  between 
the  rows.  When  the  per- 
manent roots  are  well 
started,  the  temporary  roots 
wither  and  die,  leaving  the 
plant  to  depend  upon  the 
permanent  system.  Deep 
planting  of  the  seed  does 
not  secure  deep  rooting 
except  for  the  temporary 
system,  and  in  most  sea- 
sons is  harmful  rather  than 
helpful,  since  the  deep 
planting  makes  it  more 
difficult  for  the  young 
plant  to  get  its  leaves  up 
through  the  soil  and   into 

the  air,  from  which  it   must  obtain  its  supply   of  carbon 

for  the  formation  of  tissue. 


Fig.  12.— a  Glass  Case  Used  for 
Observing  the  Early  Growth  and 
Development  of  the  Corn  Plant. 


EXERCISE  16.     A  STUDY  OF  THE   MATURE   CORN 
PLANT 

Equipment:     Spade  and  note  book. 

Method:  Carefully  dig  up  a  mature  stalk  of  corn  and 
make  a  careful  study,  (1)  of  the  parts  below  ground,  and 
(2)  of  the  parts  above  the  soil. 

Discussion:  A  close  examination  of  the  parts  below 
ground  will  reveal  the  fact  that  besides  the  large  roots  that 
hold  the  plant  upright,  there  are  a  large  number  of  little 
threadlike  roots  passing  out  into  the  soil  in  all  directions. 
How  deep  would  it  be  safe  to  plow  without  injuring  these 
fine  feeding  roots?  About  the  time  the  tassels  develop  the 
large  brace  roots  appear. 

Above  the  ground  the  joints  of  the  stalk  are  called  nodes, 
and  the  portions  between  the  joints  the  internodes.  These 
intemodes  are  flattened  on  one  side.  Upon  which  side  of  the 
intemode  is  the  ear  always  found?  How  are  the  leaves 
arranged  on  the  stalk?  Notice  that  the  edges  of  the  leaves 
are  longer  than  the  central  part,  giving  the  margin  a  wavy 
appearance.  Does  this  not  help  to  prevent  the  leaves  from 
being  torn  by  the  wind? 

The  stamens  of  the  corn  plant  are  located  in  the  tassel 
at  the  upper  extremity  of  the  stalk,  while  the  pistils  are  down 
on  the  side  of  the  stalk  and  form  the  silks  of  the  ear.  Open 
an  ear  of  corn  just  after  the  silks  have  made  their  appearance 

33 


34    FIELD  AND  LABOKATORY  STUDIES  OF  CROPS 


Fig.  13. — The  Ear  to  the  Left  is  Borne  too  High  on  the  Stalk. 
Carried  at  a  Medium  Height  Should  be  Selected  for  Seed. 


Ears 


A  STUDY  OF  THE  MATURE  CORN  PLANT         35 

and  follow  the  threads  of  silk  to  their  attachment  to  the 
grains.  At  about  this  time  there  is  a  great  abundance  of 
yellow  powder  flying  in  the  air  and  scattered  over  the 
ground.  What  is  this  powder  and  why  so  much  of  it? 
When  a  corn  plant  grows  in  a  place  far  from  any  other  corn, 
what  kind  of  an  ear  does  it  develop? 

Corn  when  cut  and  cured  in  the  field  is  called  fodder, 
but  after  the  ears  have  been  removed,  the  stalks  minus  the 
ears  are  known  as  corn  stover.  When  the  entire  plant  is 
harvested  while  it  is  yet  green  and  placed  in  the  silo  with- 
out curing,  the  resulting  material  is  called  corn  silage.  Green 
corn  preserved  in  the  silo  is  used  extensively  as  a  feed  for 
dairy  cattle. 

It  is  estimated  that  there  is  produced  about  one  and 
one-third  pounds  of  stover  for  each  pound  of  ears,  and  that 
for  every  pound  of  dry  matter  in  the  roots  and  stubs  six 
pounds  are  produced  in. the  plant  above  ground. 


EXERCISE   17.     POLLINATION   OF   PLANTS 

Equipment:  A  supply  of  paper  bags  and  a  ball  of 
twine. 

Method:  (a)  Go  into  a  corn  field  when  the  silks  are 
just  beginning  to  show  beyond  the  husks  and  tie  paper 
bags  over  four  ears.  At  the  same  time  tie  bags  over  the 
tassels  of  three  or  four  plants.  Allow  the  bag  to  remain 
undisturbed  over  one  of  the  ears  for  three  or  four  weeks 
or  until  the  plant  is  ready  to  harvest.  An  examination 
at  this  time  will  show  that  no  grains  have  developed. 
Why? 

A  week  after  the  first  bagging,  cut  off  one  of  the  tassels 
and  dust  the  pollen  on  one  of  the  covered  ears,  removing 
the  bag  for  the  operation  and  replacing  it  as  soon  as  the 
pollination  is  accomplished.  One  week  later  repeat  the 
operation  with  the  other  plants.  When  the  corn  is  ready 
to  harvest  remove  the  bags  and  examine  the  ears. 

(h)  Plant  side  by  side  in  the  home  or  school  garden 
a  number  of  hills  of  yellow  and  white  corn  or  field  and 
pop  corn.  In  the  fall  when  the  corn  is  husked,  note  the 
mixture  of  two  kinds  of  kernels  on  the  same  cob.  How 
did  this  corn  become  mixed? 

Discussion:  Some  flowers  produce  seeds  while  others 
do  not.  Some  ears  of  corn  have  vacant  places  on  the  cob, 
or  poorly  filled  tips.  From  this  exercise  it  will  be  seen 
that  if  a  flower  is  to  produce  fruit,  its  pistil  must  receive 

36 


POLLINATION  OF  PLANTS 


37 


iriJp 


IL 


■  iiiiBi—w  I  III  I.; 


Fig.  14. — The  Flowering  Parts  of  the  Corn  Plant.  I'dlK  n  from  the 
Tassel  to  the  Right  must  Fall  in  the  Silks  before  the  Grain  will 
Develop. 


38    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

pollen  or  dust  from  the  same  or  another  closely  related  flower. 
In  the  corn  plant  the  silks  are  the  pistils  or  female  parts 
of  the  flower,  while  the  tassel  is  the  male  part  of  the  flower 
and  produces  the  pollen  with  which  the  silks  are  fertihzed. 
In  such  plants  as  oats  and  wheat  both  parts  of  the  flower 
develop  at  the  same  place  on  the  plant  and  are  enclosed 
within  the  glumes  or  chaff.  When  the  two  parts  are 
separated,  as  in  the  corn  plant,  it  is  necessary  that  the 
wind  or  insects  carry  the  pollen  from  the  tassel  to  the  silks 
before  the  grain  can  develop.  With  oats  and  wheat  the 
parts  are  so  arranged  that  each  flower  produces  its  own 
pollen  and  as  a  consequence  they  are  close  fertilized. 

By  putting  the  pollen  of  one  kind  of  a  plant  on  the  pistil 
of  another  closely  related  plant,  the  plant  breeder  some- 
time originates  a  new  variety.  Plants  so  produced  are 
called  hybrids  or  crosses.  The  hybrid  plants  are  some- 
times very  much  superior  to  either  parent,  but  it  frequently 
happens  that  the  crossing  results  in  the  production  of 
plants  that  are  inferior  to  the  parent  forms. 


EXERCISE   18.      THE   SELECTION    OF   SEED   CORN  IN 
THE  FIELD 

Equipment:    A  field  of  corn  just  ready  to'  be  harvested. 

Method :  Each  student  should  be  required  ij^  select  ten 
seed  ears  from  the  plants  in  the  field.  The  best  time  to 
make  this  selection  is  just  before  the  corn  is  harvested. 
The  seed  ears  may  be  gathered  at  the  time  the  selection  is 
made,  but  it  is  better  to  mark  them  and  allow  them  to 
remain  attached  to  the  stalk  until  fully  matured.  Th6 
plants  may  be  marked  by  breaking  over  the  stalk  just 
above  the  ear  or  by  spotting  the  husk  of  the  ear  with  paint, 
then  later,  when  the  corn  is  being  husked  either  from  the 
standing  stalks  in  the  field  or  from  the  shock,  the  selected 
ears  can  be  identified  and  placed  in  a  separate  pile. 

Discussion:  Good-sized  ears  growing  slightly  below  the 
middle  of  the  stalk  should  be  selected.  Plants  with  ea,FS 
borne  high  on  the  stalk  are  frequently  late  in  maturing  a^d 
are  more  easily  blown  over  than  those  carrying  the  ear  low^. 
Selections  should  be  made  from  strong,  vigorous  plants 
growing  under  normal  stand.  A  plant  growing  in  a  hill  with 
two  other  plants  should  be  rated  much  higher  for  haying 
produced  a  good,  large  ear  than  a  stalk  growing  in'^il  hill  by 
itself.  Many  of  our  most  productive  plants  owe  their 
superiority  to  their  inunediate  environment — extra  food, 
sunlight  and  moisture — which  they  secure  as  the  result  of  a 
thin  stand.     It  is  probable  that  four  out  of  every  five  ears 

39 


40    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 


Fig.  15. — Selecting  Seed  Corn  in  the  Field.  Stalks  Bearing  Desirable 
Ears  are  Broken  over  so  that  they  may  be  Identified  at  Harvest 
and  the  Ears  Saved  for  Seed. 


THE  SELECTION  OF  SEED  CORN  IN  THE  FIELD    41 

of  seed  corn  selected  from  the  crib  owe  their  excellent 
appearance  to  this  lack  of  competition  in  the  field.  The 
intelligent  selection  of  seed  ears  from  the  stalk  in  the  field 
is  helpful,  since  we  can  be  sure  that  the  excellence  which 
the  ear  possesses  is  due  to  something  wrapped  up  in  the  seed 
and  not  to  something  which  has  happened  to  the  plant. 

Both  heredity  and  environment  are  responsible  for  what 
we  see  as  we  look  over  a  field  of  corn  with  its  thousands  of 
individual  plants,  no  two  of  which  possess  like  characters 
or  the  same  possibilities.  The  work  of  the  corn  grower, 
young  or  old,  is  to  determine  that  which  is  temporary  or 
accidental  and  that  which  is  lasting  and  may  be  inherited. 


EXERCISE   19.     THE  STORAGE   OF  SEED  CORN 

Equipment:     Germination  box. 

Method:  At  corn-harvest  time  in  the  fall,  each  pupil 
should  select  twelve  ears  of  corn  from  the  field.  Three  of 
the  ears  should  be  left  on  the  stalks,  the  plants  being  cut 
and  set  against  the  fence.  The  remaining  nine  ears  should 
be  husked  and  divided  into  three  lots  of  three  ears  each. 
One  lot  should  be  stored  in  the  cellar,  another  overhead  in 
the  crib  and  a  third  in  some  warm  place  in  the  house.  At 
some  convenient  time  during  the  winter,  separate  germina- 
tion tests  should  be  made  on  all  of  the  ears  and  the  results 
of  the  test  reported  in  the  following  table: 


Lot  No. 

Method  of  Storage. 

Average  per  cent,  of  Germination. 

1 

2 

3 

4 

Discussion:  When  seed  corn  is  selected  from  the  stalk 
in  the  field,  two  bushels  of  ears  should  be  selected  for  every 
bushel  that  will  be  needed  for  planting  the  following  spring. 
This  precaution  is  necessary,  since  some  of  the  ears  will  need 
to  be  discarded  after  they  are  husked.  It  is  well  to  leave  the 
selected  ears  on  the  stalk  until  they  are  well  matured  and 

42 


THE  STORAGE  OF  SEED  CORN 


43 


Fig.   16. — Seed  Corn    Storage  Rack  Made  from  a  Short  Section  of 
Woven-wire  Fence. 


44    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 


hardened.  Before  freezing  weather  they  should  be  husked 
and  stored  in  some  dry,  well-ventilated  place.  Before 
planting  time  in  the  spring  the  seed  ears  should  be  spread 
out  on  the  floor  or   on  a  table  in  a  well-lighted  room  and 

Blllil 
■ 
I 


Fig.  17. — Seed  Corn  Storage  Rack  Made  of  2X4  Uprights  and  Lath 
Nailed  on  Edge. 

after  a  careful  examination  all  the  poorer  ears  should  be 
rejected. 

In  this  final  selection  the  following  rules  should  be 
observed : 

Rule  1.     Select  ears  of  a  medium  size  for  your  locality. 


THE  STORAGE  OF  SEED  CORN  45 

The  small-eared  early  types  which  do  not  utilize  the  entire 
growing  season  will  not  produce  the  maximum  yield.  The 
lai-ge-eared  types  which  are  so  late  that  they  cannot  mature 
a  hard,  solid  ear  also  fail  of  the  maximum  production  and 
yield  a  product  which  is  inferior  both  for  market  and  for 
home  consumption. 

Rule  2.  Select  ears  that  are  very  heavy  for  their  size. 
The  yield  seems  to  be  more  closely  associated  with  weight 
of  ear  than  any  other  one  quality. 

Rule  3.  Select  ears  of  a  bright,  healthy  color.  Ears  of  a 
dull  or  pale  color  are  usually  immature  or  have  been  exposed 
to  the  weather.  The  color  indicates  poor  seed  condition  and 
low  vitahty. 

Rule  4.  Select  ears  with  grains  of  uniform  size  and  shape. 
Aside  from  its  indication  as  to  trueness  of  type,  uniform- 
ity of  grain  is  of  considerable  importance  in  getting  an  even 
distribution  of  seed  and  a  uniform  stand,  when  machine 
planting  is  practiced. 

Finally,  all  the  selected  ears  should  be  subjected  to  the 
germination  test. 


EXERCISE   20.     JUDGING   CORN   EARS 

Equipment:  A  five-ear  sample  of  corn  for  each  member 
of  the  class;  tape  measure;  a  pair  of  postal  scales. 

Method:  Provide  each  pupil  with  five  ears  of  corn  and 
let  him  practice  scoring,  using  the  score  card  given  or  one 
secured  from  your  Agricultural  College.  Each  student 
should  score  half  a  dozen  or  more  five-ear  samples  before 
this  exercise  is  passed.  Number  all  of  the  ears  by  tying  to 
each  a  small  numbered  tag  or  sticking  a  numbered  tab  on 
the  butt  of  each  cob.  Have  each  pupil  provide  himself  with  a 
score  card  ruled  as  shown  on  page  48,  providing  one  column 
for  each  ear  of  corn,  and  score  the  individual  ears  of  a 
five-ear  sample.  The  figures  in  the  score  card  between  the 
first  two  perpendicular  lines  show  the  number  of  "  points  " 
that  should  be  given  for  a  perfect  ear,  e.g.,  if  the  pupil 
thinks  ear  No.  4  is  nearly  perfect  in  shape  he  would  probably 
mark  9  in  line  1,  column  4,  as  shown  in  the  table.  Each 
pupil  should  examine  carefully  each  ear  of  corn  and  put 
down  on  his  score  card,  in  the  column  of  the  same  number 
as  the  ear  of  corn,  his  estimate  of  the  qualities  named  on 
each  line  at  the  left,  except  line  3 — vitality — which  should 
not  be  filled  in  until  after  the  ears  have  been  subjected  to 
the  germination  test  as  directed  in  Exercise  22. 

Then  compute  the  germinating  value  of  the  different 
samples  on  the  basis  of  20  for  a  perfect  ear,  as  shown  in  the 
score  card,  and  give  each  ear  its  proper  rating  in  line  3  of 

46 


JUDGING  CORN  EARS 


47 


Fig.  18. — An  Ideal  Ear  of  Corn.     (MisKouri.) 


48    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

the  score  card.  Now  add  up  the  different  columns  of  figures 
in  the  score  card  and  by  means  of  the  totals  select  the  best 
two  ears. 

Continue  the  exercise  by  treating  each  five-ear  sample 
as  a  unit,  and  scoring  them  in  the  same  manner  as  the  in- 
dividual ears. 

SCORE   CARD   FOR  CORN 


Points. 

Perfect 
Score. 

1 

2 

3 

4 

5 

1.  Shape  of  ear 

10 

5 

20 
5 
5 
5 
5 
5 
5 
5 

10 
10 
10 

2.  Purity  of  color  in  grain  and  cob .  . 

3.  Vitality,    maturity,    germinating 
power 

4.  Tips  of  ears 

5.  Butts  of  ears 

6.  Uniformity  of  kernels 

7.  Shape  of  kernels 

8.  Length  of  ear 

1 

9.  Circumference  of  ear 

10.  Furrows  between  rows 

11.  Space  between  kernels  at  cob. .  .  . 

12.  Proportion  of  grain  to  cob 

13.  Composition  and  feeding  value.  . 

Total 

100 

In  order  to  understand  the  meaning  of  all  the  points 
listed  in  this  score  card  it  is  well  to  write  to  the  State  Agri- 
cultural College  or  to  the  State  Corn  Breeders'  Association, 
if  there  is  one,  for  an  explanation  of  the  official  score  card 
used  in  your  State;  or  it  may  be  possible  to  get  someone 
from  the  Agricultural  College  to  come  to  your  school  or 
county  teachers'   meeting  and   explain   the  score  card  in 


JUDGING  CORN  EARS  49 

detail.  A  brief  explanation  of  the  score-card  points  will  be 
found  in  the  following  discussion: 

Discussion:  The  points  on  the  score  card  are  explained, 
as  follows: 

1 .  Shape  of  Ear.  A  good  ear  should  be  nearly  cylindrical. 
This  will  permit  of  an  equal  number  of  rows  the  entire 
length  of  the  ear  and  will  insure  grains  of  uniform  size. 


Fig.  19. — Diagram  Showing  Desirable  Kernel  Shapes.  The  Three  at 
the  Bottom  of  the  Circle  and  the  Four  to  the  Right  are  Ideal. 
(Adapted  from  Lyon  and  Montgomery.) 

Uniformity  in  size  of  grain  is  important  because  the  planter 
will  give  a  more  uniform  drop. 

2.  Purity  of  Color  in  Grain  and  Cob.  A  uniform  color  of 
grain  indicates  a  pure  variety.  Yellow  corn  should  have 
a  red  cob  and  white  corn  a  white  cob. 

3.  Vitality,  Maturity  and  Germinating  Power.  Corn  that 
is  to  be  used  for  seed  should  have  good  vitality.  The 
germination  box  is  tlic  only  reliable  test  for  vitality. 


50    FIELD  AND  LABORATOEY  STUDIES  OF  CROPS 

4.  Tips  of  Ears.  The  tips  should  be  well  filled  and  if 
the  ears  are  full  size  it  is  desirable  to  have  the  tip  of  the  cob 
capped  over  with  grains. 

5.  Butts  of  Ears.  This  end  of  the  cob  should  be  well 
rounded  over  with  grains  and  show  a  medium-sized  attach- 
ment for  the  shank. 

6.  Uniformity  of  Kernels.  Kernels  should  be  uniform 
in  size,  otherwise  the  planter  will  fail  to  give  a  uniform  drop. 

7.  Shape  of  Kernels.  The  kernels  should  be  slightly 
wedge  shape  and  retain  their  thickness  well  down  to  the  tip. 

8.  Length  of  Ear.  The  proper  length  for  an  ear  will 
depend  upon  the  locality.  A  standard  length  should  be 
established  by  getting  the  average  length  of  a  number  of 
good  matured  ears. 

9.  Circumference  of  Ear.  The  circumference  should  be 
about  three-fourths  to  four-fifths  of  the  length  when  meas- 
ured about  two  inches  from  the  butt. 

10.  Furrows  between  the  Rows.  The  space  between  the 
rows  should  be  small. 

11.  Space  between  the  Kernels  at  Cob.  The  kernels 
should  retain  their  thickness  down  almost  to  the  tip  with  no 
space  between  them  at  the  point  where  they  are  attached 
to  the  cob. 

12.  Proportion  of  Grain  to  Cob.  A  medium-sized  cob 
with  deep  grains  is  to  be  desired.  The  percentage  of  grain 
should  be  between  83  and  86  for  most  varieties  of  corn. 

13.  Composition  and  Feeding  Value.  A  large  proportion 
of  hard  fiinty  endosperm  is  desirable. 


EXERCISE    21.     TO    STUDY    THE    EFFECT    OF    STAND 
UPON  THE  YIELD  OF  CORN 

Equipment:  Basket;  50-foot  tape  line;  a  pair  of  spring 
balances. 

Method:  As  soon  as  corn  is  ripe,  go  to  a  nearby  field 
and  after  selecting  a  representative  row,  measure  off  one- 
hundredth  of  an  acre  *  and  count:  (1)  the  total  number  of 
stalks  and  (2)  the  number  of  stalks  which  have  no  ear. 
Compare  the  total  number  of  plants  actually  found  with 
the  number  necessary  to  constitute  a  perfect  stand.  Husk 
and  weigh  the  com,  count  the  number  of  ears  and  calculate 
the  average  weight.  Make  the  necessary  calculations  and 
fill  in  the  blanks  in  the  accompanying  form: 


Number  of  stalks  necessary  for  perfect  stand 

Number  of  plants  found 

Per  cent  of  perfect  stand 

Total  weight  of  corn  harvested 

Number  of  ears  harvested 

Average  weight  of  ears 

Yield  in  bushels  i)er  acre 

Yield  for  a  perfect  stand  with  each  stalk  producing  an 

average-sized  ear 

Yield  for  a  perfect  stand  if  each  stalk  had  produced  a 
lAh.  ear 


*  If  the  rows  are  3|  feet  apart,  125  feet  will  make  a  hundredth  part 
of  an  acre. 

61 


52     FIELD  AND  LABOEATOEY  STUDIES  OF  CEOPS 

Discussion :  Many  farmers  plant  their  corn  fields  with- 
out having  tested  the  vitaHty  of  their  seed  ears.  This 
neglect  frequently  results  in  a  poor  stand  and  a  low  yield 
of  corn.  With  better  cultural  methods  and  more  attention 
given  to  the  selection  of  good  seed  it  is  possible  to  double 
the  average  yield  of  corn  in  many  communities. 

One  of  the  most  important  steps  in  securing  good  seed  is 
the  elimination  of  the  ears  that  will  not  grow.  While  ears 
having  weak  or  dead  kernels  can  sometimes  be  discarded  by 
their  general  appearance,  it  is  not  always  possible  to  detect 
them  by  this  means.  The  only  safe  way  is  to  plant  the 
kernels  and  see  if  they  will  grow.  This  can  be  done  by 
taking  several  kernels  from  each  ear  and  planting  them  in 
a  small  box  filled  with  sawdust,  sand,  or  soil.  A  box  10x20 
inches  and  three  inches  deep  is  a  convenient  size.  Detailed 
directions  for  making  the  germination  test  are  given  in 
Exercise  22. 


EXERCISE  22.     TO  TEST  THE  VITALITY  OF  SEED  CORN 

Equipment:  Fifty  ears  of  corn;  a  germination  box; 
sand  or  sawdust  sufficient  to  fill  the  box;  a  piece  of  muslin 
10X20  inches. 

r.  ._      _  Method:     Number  the  ears  and 

place  them  in  consecutive  order  on  a 
y      table  or  a  bench  where  they  will  remain 


Fig.  20. — The  Sandbox  Germinator  Will  Pick  out  the  Dead  Ears. 
(Courtesy  of  Extension  Department.) 


undisturbed  until  the  close  of  the  exercise.  The  germination 
box  may  be  constructed  at  the  school  or  home  of  one  of 
the  pupils.  It  consists  of  a  shallow  wooden  box  3  X 10X20 
inches  inside  measurement  and  three  inches  deep.  Along 
all  four  sides  of  the  box  are  saw  cuts  one  inch  deep  and  two 

53 


54    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

inches  apart.  The  germinator  is  prepared  by  filling  the 
box  to  within  one  inch  of  the  top  with  moist  sand.  The 
surface,  having  been  leveled  and  compacted  by  means  of  a 
smooth  block  of  wood,  is  marked  off  into  small  squares  2X2 


Fig.  21. — Four  Sections  from  the  Germination  Box.  Nos.  1  and  2 
Show  Strong,  Vigorous  Growth.  No.  3  is  Weak,  while  No.  4 
Shows  Three  Dead  and  Three  Weak  Grains. 

inches,  by  means  of  a  cord  which  is  laced  back  and  forth 
through  the  saw  cuts  in  the  edge  of  the  box.  Beginning  in 
the  upper  left-hand  corner,  the  squares  are  numbered  from 
one  to  fifty. 


TO  TEST  THE  VITALITY  OF  SEED  CORN 


55 


Commencing  with  ear  No.  1,  remove  six  kernels,  two  near 
the  butt  on  opposite  sides,  two  near  the  middle  and  two  near 
the  tip.  Place  the  six  kernels  in 'regular  order,  germ  side 
up,  in  the  germinator  in  Square  No.  1  and  proceed  with  Ear 
No.  2  in  the  same  manner,  placing  the  kernels  from  it  in 
Square  No.  2.  Repeat  this  process  until  all  of  the  ears  have 
been  sampled. 

After  the  grains  are  all  in  place  cover  the  surface  of  the 
sand  with  a  square  of  muslin  and  add  sand  until  the  box  is 
level  full.  Moisten  the  sand  thoroughly  and  keep  it  wet 
throughout  the  exercise. 

The  germinator  should  be  kept  at  a  temperature  of  70°  to 
80°  F.,  during  the  day,  but  at  night  it  may  fall  to  50°  or  60° 
without  harm.  At  the  end  of  five  or  six  days  the  cloth  should 
be  carefully  rolled  back  in  order  to  expose  the  squares  for 
inspection.  Count  the  grains  that  have  germinated  in  each 
square  and  record  the  numbers  in  the  following  diagram: 


1 

2 

3             4 

5 

6 

7 

8 

9 

10-: 

After  careful  examination,  discard  the  ears  whose  num- 
bers correspond  to  the  square  in  which  the  grains  did  not 
grow  or  where  germination  was  weak  and  unsatisfactory. 


56     FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

Discussion:  It  matters  not  how  much  food  is  avail- 
able to  the  plants,  how  well  prepared  the  seed  bed,  or  how 
great  the  amount  of  moisture  conserved,  the  best  results 
cannot  be  obtained  unless  good  seed  is  planted.  Hereto- 
fore, much  more  rapid  advancement  has  been  made  toward 
cultural  methods  than  toward  the  securing  of  good  seed. 
Many  have  never  stopped  to  consider  what  constitutes  good 
seed.  In  good  seed  there  must  be  stored  in  the  germ  that 
which  we  call  life,  or,  as  we  commonly  say,  the  seed  must 
have  vitality.  Very  few  do  more  than  look  at  an  ear  to 
determine  its  vitality.  This  is  a  great  mistake  and  fre- 
quently results  in  a  poor  stand  and  a  low  yield.  Without 
a  perfect  stand,  the  largest  possible  yield  cannot  be  expected. 
If  time  is  taken  to  count  the  stalks  in  one  hundred  consecutive 
hills,  the  average  corn  grower  will  doubtless  be  surprised  to 
find  far  from  a  perfect  stand.  He  will  probably  find  not 
more  than  75  per  cent  or  80  per  cent  of  the  stalks  that 
should  be  there.  With  such  a  stand  and  an  allowance  of 
from  5  per  cent  to  10  per  cent  for  barren  stalks,  some  explana- 
tion can  be  made  for  the  low  yield.  There  are  on  the  aver- 
age ear  about  900  kernels  suitable  for  seed.  If  out  of  every 
hundred  ears  planted  four  or  five  lack  vitality,  it  will  mean 
at  least  2000  fewer  stalks  in  the  field  per  100  seed  ears 
planted. 


EXERCISE  23.     TESTING  THE  CORN  PLANTER 

Equipment:  A  two-row  corn  planter;  a  quantity  of 
shelled  corn. 

Method:  Examine  the  planter  and  find  answers  to  the 
following  questions: 

Has  the  planter  a  drill  or  full  hill  drop? 

How  is  the  change  made  from  drill  to  hill  drop? 

Has  the  planter  edge  selection  or  flat  plate? 

Will  the  seed  box  tip  over? 

How  many  valves  in  each  planter  shank? 

Is  the  furrow  opener  a  stub  or  curved  runner  or  a  disk? 

Set  the  planter  to  drop  three  grains  to  the  hill  and  meas- 
ure off  a  distance  of  one  hundred  feet  on  a  smooth  level 
stretch.  Draw  the  planter  over  this  distance  and  count 
the  kernels  dropped  in  each  hill.  Repeat  the  test  three 
times  and  record  the  results. 

Change  the  planter  to  the  drill  drop  and  test  in  the  same 
manner. 


First 
Count. 


Second 
Count. 


Third 
Count. 


Average. 


Number  of  hills  with  no  grains . 
Number  of  hills  with  1  grain .  .  . 
Number  of  hills  with  2  grains .  . 
Number  of  hills  with  3  grains .  . 
Number  of  hills  with  more  than 
3  grains 


57 


58    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

Divide  the  total  number  of  grains  dropped  by  the  num- 
ber of  hills,  to  get  the  average  number  of  grains  per  hill. 
If  the  results  are  very  unsatisfactory,  change  the  plates 
in  the  bottom  of  the  grain  boxes  and  repeat  the  test. 

Discussion:  A  good  corn  planter  should  have  several 
sets  of  plates,  in  order  that  adjustments  may  be  made  for 
dropping  accurately,  small,  medium,  or  large  grains.  Pre- 
vious to  planting  time,  the  planter  should  be  put  in  order 
and  the  accuracy  of  its  drop  tested.  In  the  preparation  of 
seed  corn,  the  small  and  irregular-shaped  grains  should  be 
removed  from  the  butts  and  tips  of  the  ears  and  discarded. 
As  a  further  aid  to  the  planter,  the  shelled  seed  corn  may  be 
graded  to  uniform  size  by  passing  it  through  a  set  of  sieves, 
the  first  one  of  which  will  hold  back  the  extra  large  grains, 
and  the  second  of  which  will  retain  the  medium-sized  grains 
but  allow  the  very  small  to  pass. 


EXERCISE    24.     TO   STUDY  THE   NECESSITY  FOR 
PROPER  CULTURAL  METHODS  FOR  CORN 

Equipment:    Spade;  yardstick. 

Method :  Dig  down  beside  a  corn  plant  in  the  field  to  a 
depth  of  two  or  three  feet  and  carefully  wash  the  soil  away 
from  the  roots.  Make  a  study  of  the  root  system  and, 
after  reading  the  discussion  which  follows,  write  a  report  on 
''Cultural  Methods  for  Corn." 

Discussion:  The  principal  objects  of  cultivation  are: 
(1)  to  save  moisture,  (2)  to  kill  weeds  and  (3)  to  make  plant 
food  available. 

Cultivation  by  means  of  a  harrow  or  weeder  may  begin 
three  or  four  days  after  planting  or  as  soon  as  the  weeds 
begin  to  come  through  the  soil.  This  process  should  be 
repeated  frequently,  the  principal  object  being  to  kill  the 
weeds.  Workings  with  the  cultivator  should  be  given  as 
the  surface  soil  becomes  compact,  especially  after  every 
heavy  rain. 

From  the  time  that  the  ear  begins  to  form  until  it  is 
nearly  matured,  a  large  amount  of  moisture  will  be  required 
to  supply  the  necessary  food  material.  This  period  will 
extend  from  the  latter  part  of  June  to  the  middle  of  August. 
If  the  moisture  is  to  be  conserved,  frequent  cultivation  must 
be  continued  as  late  as  possible  into  the  summer,  even  after 
the  plant  has  tasseled.  A  study  of  the  development  of  the 
roots  of  the  corn  plant  will  disclose  the  facts  that  at  first 


60     FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

the  roots  are  similar  to  tap  roots  which  have  a  tendency  to 
go  down  in  search  of  moisture  and  food,  and  that  gradually 
lateral  roots  are  formed.  In  the  course  of  sixty  or  seventy 
days  the  soil  will  be  filled  with  roots  from  hill  to  hill.  If 
shallow  cultivation  has  been  practiced,  these  roots  will 
come  near  the  surface  of  the  soil,  where  they  will  find  the 
greatest  amount  of  available  plant  food. 

After  a  heavy  rain  the  greater  part  of  the  water  which 
enters  the  soil  passes  down  through  until  it  reaches  a  place 
where  all  of  the  openings  between  the  soil  particles  are  com- 
pletely filled  with  free  water.  During  the  time  between 
rains,  the  plants  must  get  their  moisture  from  this  supply 
deep  down  in  the  soil.  The  process  by  which  this  water 
rises  in  the  soil  is  called  capillarity.  This  capillary  water 
is  sometimes  called  film  moisture,  because  it  is  spread  out  in 
a  thin  film  over  each  soil  particle.  Persistent  shallow  cul- 
tivation forms  a  mulch  over  the  surface  of  the  soil  and  pre- 
vents excessive  loss  of  moisture  by  evaporation. 


PROPER  CULTURAL  METHODS  FOR  CORN    61 


FffOM 
l£AV£S 


Fig.  22. — Continuous  Thorough  Cultivation  is  Necessary  to  Prevent 
the  Loss  of  Moisture  at  the  Surface  of  the  Soil. 


EXERCISE  25.     THE  PRODUCTION   OF  CORN  IN  THE 
UNITED    STATES 

Equipment:  Yearbook  of  the  United  States  Depart- 
ment of  Agriculture.* 

Method:  From  the  Yearbook  obtain  the  figures  for 
the  production  of  corn  in  each  State  of  the  United  States. 
Represent  the  geographical  distribution  of  the  areas  of 
large  production  on  the  accompanying  map  by  the  use  of 
appropriate  shadings.  Those  States  which  produce  more 
than  100  million  bushels  should  be  shaded  black;  those 
producing  more  than  50  million  and  less  than  100  million 
a  lighter  shade;  and  those  producing  less  than  50  million 
left  unshaded. 

Discussion :  Climatic  and  soil  conditions  determine  the 
distribution  of  the  crops  in  the  United  States.  The  greater 
part  of  the  corn  grown  in  this  country  is  produced  in  seven 
or  eight  States  of  the  Middle  West,  which  are  known  as 
the  corn-belt  States.  Wheat  is  more  widely  distributed, 
while  oats  are  confined  largely  to  the  North  Central  States. 

The  United  States  produces  about  four-fifths  of  the 
world's  corn  crop. 

The  corn  belt  states  of  this  country  appear  to  have  the 
best  combination  of  sunshine,  temperature,  rainfall  and 
soils  for  the  production  of  corn.  Water  is  undoubtedly 
the  most  important  factor  in  the  successful  culture  of  corn. 
A  study  of  corn  yields  in  connection  with  the  records  of  the 
Weather  Bureau  has  brought  out  the  fact  that  there  is  a 

*  A  copy  of  this  publication  can  be  obtained  free  of  cost  by  applica- 
tion to  yoilr  Senator  or  Representative  at  Washington,  D.  C. 

62 


PRODUCTION  OF  CORN  IN  THE  UNITED  STATES    63 

very  direct  connection  between  rainfall  and  yield  of  corn. 
The  yield  does  not  depend  upon  the  total  rainfall  alone, 
but  upon  its  distribution  throughout  the  growing  season. 


Fig.  23. — Distribution  of  the  World's  Corn  Crop.  United  States  Pro- 
duces Four-fifths  and  the  Rest  of  the  World  One-fifth  of  the  Total 
Crop. 

The  most  favorable  condition  for  the  growth  of  corn  is 
heavy  rains  at  considerable  intervals,  with  clear  weather 
and  abundant  sunshine  in  the  meantime. 


64    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 


EXERCISE  26.     STUDY  OF  A  HEAD  OF  WHEAT 

Equipment:  A  sufficient  number  of  wheat  heads  to 
supply  eacli  member  of  the  class  with  a  head  of  bearded  and 
one  of  smooth  wheat. 

Method :  Make  a  careful  examination  of  the  two  heads 
and  locate  all  of  the  parts.  Make  a  drawing  of  the  entire 
spike,  then  separate  the  parts  and  make  a  detailed  sketch 
showing  each  part  in  place-  Remove  a  kernel  from  one  of 
the  spikelets  and  make  a  drawing  showing  the  crease  side, 
the  germ  side,  and  a  cross-section  view.  All  drawings 
should  be  at  least  one  inch  in  height. 

After  the  detailed  study  is  finished,  fill  out  the  following 
table  with  data  obtained  by  the  examination  of  five  average- 
size  heads. 


1 

2 

3 

4 

5 

Length  of  head 

Number  of  developed  spikelets 

Total  number  of  kernels 

Average  number  of  kernels  per  spikelet 

How  many  average-size  heads  must  there  be  per  acre  to 
give  a  yield  of  20  bushels  of  threshed  grain? 

Thresh  by  hand  100  average  heads  and  weigh  the 
threshed  grain. 

Discussion :  The  head  of  wheat  is  called  a  spike,  and  is 
composed  of  spikelets  arranged  to  alternate  on  two  sides  of  a 

65 


66    FIELD  AND  LABOKATORY  STUDIES  OF  CROPS 


STUDY  OF  A  HEAD  OF  WHEAT  67 

central  stem  called  the  rachis.  Each  fully  developed  spikelet 
has  two  or  more  grains  and  an  undeveloped  flower.  When 
only  two  grains  develop  in  a  spikelet  each  grain  is  enclosed 
in  an  outer  glume,  a  flowering  glume,  and  a  thin  inner  glume 
called  the  palea.  When  a  third  kernel  is  present,  it  has  no 
outer  glume,  but  is  enclosed  between  the  flowering  glume 
and  palea.  The  germ  of  the  kernel  is  at  the  base  and  faces 
toward  the  outside  of  the  spikelet;  the  creased  side  of  the 
grain  faces  toward  the  center  of  the  spikelet  and  is  covered 
by  the  palea.  Extending  from  the  upper  end  of  the  kernel 
is  a  tuft  of  very  fine  hairs  called  the  brush. 


EXERCISE  27.  EARLY  DEVELOPMENT  OF  THE  WHEAT 

PLANT 

Equipment:  Young  wheat  plants  one,  two,  three  and 
four  weeks  old  a  part  of  which  have  been  planted  one  inch 
deep  and  the  remainder  three  inches  deep. 


Fig, 


26.— The  Early  Growth  of  the  Wheat  Plant.  S-S  is  Soil  Surface. 
Note  the  Fine  Root  Hairs  on  A .  The  Plant  to  the  Left  of  C  Shows 
the  Temporary  Roots  Formed  when  the  Grain  is  Planted  Deep. 
Directly  above  C  is  the  Same  Plant  a  Few  Days  Later. 

68 


EARLY  DEVELOPMENT  OF  THE  WHEAT  PLANT    69 

Method:  Follow  the  directions  given  for  the  study  of 
the  early  development  of  the  corn  plant  in  Exercise  15. 

Discussion:  The  roots  of  the  wheat  plant  comprise 
both  a  temporary  and  a  permanent  set.  When  the  kernel 
is  placed  in  a  warm  moist  soil  it  starts  to  grow,  and  sends 
out  a  whorl  of  three  small  roots  which  supply  the  temporary 
connection  between  the  plant  and  the  soil.  After  the  leaves 
unfold  above  ground  a  permanent  set  of  roots  develop  about 
an  inch  below  the  surface,  regardless  of  the  depth  at  which 
the  grain  has  been  planted.  These  permanent  roots  increase 
rapidly  in  length  and  develop  into  a  fibrous  root  system 
which  serves  the  plant  for  the  remainder  of  its  life.  The 
greater  part  of  the  roots  of  the  mature  plant  are  to  be  found 
in  the  surface  fifteen  to  twenty  inches  of  soil,  but  in  loose 
mellow  soil  some  of  the  larger  roots  may  go  down  five  to  six 
feet. 

The  depth  of  seeding  for  wheat  will  vary  with  the  kind 
of  soil,  amount  of  moisture  and  the  fineness  of  the  seed- 
bed. Wheat  may  be  seeded  deeper  in  a  sandy  than  in  a 
clay  soil  and  it  is  desirable  to  sow  deeper  in  a  dry  than  in  a 
moist  soil.  Under  average  conditions  it  is  desirable  that 
the  seed  be  covered  with  about  one  inch  of  moist  soil. 
On  uneven,  cloddy  ground  it  is  necessary  to  put  some  of 
the  grains  deeper  than  is  usual  in  order  to  be  sure  that 
all  grains  will  be  covered. 


EXERCISE  28.     JUDGING  WHEAT 

Equipment:  A  number  of  peck  samples  of  wheat;  a 
grain  tester;  a  pair  of  good  balances. 

Method:  Make  a  careful  examination  of  each  sample 
and  record  the  scores  on  the  following  score  card : 


Perfect 
Score. 

Number  of  Sample. 

1 

2 

3     . 

4 

5 

Weight  per  bushel 

25 

20 
10 
15 
15 
10 
5 

Soundness 

Purity 

PluniDness.                 

Uniformity  in  hardness 

Uniformity  in  color 

Uniformity  in  size  of  grains. .  .  . 

Total 

100 

Explanation : 

1.  Weight  per  bushel — 25. 

Wheat  should  weigh  sixty  pounds  per  measured  bushel. 
Cut  two  points  for  each  pound  below  this. 

2.  Soundness — 20. 

There  should  be  no  sprouted,  cracked,  smutty,  musty, 
binburned,  or  otherwise  damaged  grains  in  the  sample. 
Cut  two  points  for  each  per  cent  of  unsound  grains. 

3.  Purity— 10. 

The  sample  should  be  free  from  mixture  or  foreign 

70 


JUDGING  WHEAT  71 

matter  of  any  kind.     Cut  one  point  for  each  per  cent  of 
foreign  matter. 

4.  Plumpness — 15. 

The  grains  should  be  well  filled  and  plump.     Cut  one 
point  for  each  two  per  cent  of  shriveled  grains. 

5.  Uniformity  in  hardness  and  texture — 15. 

The  berries  should  be  uniform  in  hardness  and  texture. 
In  a  lot  of  100  grains  determine  three  classes:    (1)  grains 


Fig.  27. — Kettle  for  Determining  the  Weight  per  Measured  Bushel. 
The  Vessel  Should  be  Filled  to  Overflowing  by  Pouring  the  Grain 
from  a  Bag  Held  about  Two  Inches  above  the  Top.  Before 
Weighing  the  Grain  is  Leveled  Off  by  a  Diagonal  Stroke. 

hard  and  vitreous.     (2)  grains  soft  and  starchy,  (3)  grains 
intermediate. 

Cut  one  point  for  each  three  per  cent  representing  class 
2  and  one  point  for  each  ten  per  cent  in  class  3.  In  a  fairly 
uniform  sample  two  classes  only  may  be  distinguished. 

6.  Uniformity  in  color — 10. 

Cut  one  point  for  each  three  per  cent  not  uniform  in 
color  with  the  bulk  of  the  sample. 

7.  Uniformity  in  size — 5. 

Cut  one  point  for  each  four  per  cent  of  undersized  grains. 


EXERCISE  29.     THE  PRODUCTION  OF  WHEAT  IN  THE 
UNITED    STATES 

Equipment:  Yearbook  of  the  United  States  Department 
of  Agriculture. 

Method :  From  the  Yearbook  obtain  the  figures  for  the 
production  of  wheat  in  each  State  in  the  United  States. 
Represent  the  geographical  distribution  of  the  areas  of  large 
production  on  the  accompanying  blank  map  by  the  use  of 
appropriate  shadings.     Those  States  which  produce  more 


United  States.  Rest  of  the  World. 

Fig.  28.— Of  the  Total  World's  Wheat  Crop,  United  States  Produces 
about  One-fifth. 

than  50  million  bushels  should  be  shaded  black;  those 
producing  more  than  25  miUion  but  less  than  50  million 
bushels  a  lighter  shade;  and  those  having  a  production 
less  than  25  million  bushels  left  unshaded. 

Discussion:  The  United  States  is  the  largest  wheat- 
producing  country  of  the  world,  while  Russia  occupies  the 
second  place.  In  this  country  about  one-half  of  the  crop  is 
produced  in  the  North  Central  States  west  of  the  Mississippi 
River,  including  Minnesota,  Iowa,  Missouri,  North  Dakota, 
South  Dakota,  Nebraska  and  Kansas.  In  Minnesota  and 
the  Dakotas  practically  all  of  the  wheat  is  seeded  in  the 
spring,  while  in  the  other  States  the  crop  is  seeded  in  the  fall. 

72 


PRODUCTION  OF  WHEAT  IN  UNITED  STATES     73 


EXERCISE  30.     EARLY  GROWTH  OF  THE  OAT  PLANT 

Equipment:  For  this  exercise  the  same  preparation  is 
to  be  made  as  that  described  for  corn. 

Method:  Follow  the  directions  given  for  corn  in  Exer- 
cise 15. 

Discussion:  Unlike  the  wheat  grain,  the  oat  kernel  is 
enclosed  in  a  loose  hull,  which  is  considered  as  a  part  of  the 
grain.  In  the  germination  of  the  grain  and  the  formation 
of  the  temporary  and  permanent  root  systems,  the  oat  is 
similar  in  its  development  to  wheat.  In  the  South,  where  the 
winters  are  mild,  oats  are  seeded  in  the  fall  and  get  their 
root  system  developed  before  cold  weather,  but  in  the  North 
the  seeding  is  delayed  until  early  spring.  It  is  essential, 
however,  that  oats  be  seeded  quite  early  in  the  spring  in 
order  that  the  plants  may  have  an  opportunity  to  come  to 
maturity  before  the  dry,  hot  summer  season  is  far  advanced. 

Experiments  concerning  the  depth  of  seeding  oats  in- 
dicate that  the  best  depth  is  from  one  to  two  inches,  but 
in  case  the  soil  is  quite  dry  a  greater  depth  may  be  desirable. 
In  some  sections  the  oats  are  seeded  broadcast  over  the 
surface  and  plowed  or  harrowed  into  the  surface  of  the 
soil  without  any  previous  preparation  of  seed  bed.  The 
best  yields  are  obtained,  however,  when  the  oats  are 
drilled  into  a  seed  bed  that  has  been  prepared  by  thorough 
disking  and  harrowing. 

74 


EARLY  GROWTH  OF   THE  OAT  PLANT 


75 


1 


EXERCISE   31.     JUDGING    OATS 

Equipment :  A  number  of  peck  samples  of  oats ;  a  grain 
tester;  and  a  pair  of  good  balances. 

Method:  Make  a  careful  examination  of  each  sample 
and  mark  the  scores  on  the  following  card : 


Perfect 
Score. 

Sample  Number. 

1 

2 

3 

4 

5 

Wfiiffht  Der  bushel              .  .  . 

35 
20 
15 
10 
20 

Soundness           

Color              

Purity        

Per  cent  of  hull                      .... 

Total    

100 

Explanation:  In  this  score  card  oats  are  judged  prin- 
cipally from  the  market  standpoint.  It  is  not  possible 
to  make  a  score  card  which  can  be  used  to  judge  oats 
from  the  feeder's  and  the  miller's  standpoint,  and  at  the 
same  time  be  used  to  detennine  the  quality  of  the  grain 
for  seeding.  Different  points  would  be  used  in  each  case, 
and  different  values  given  them. 

1.  Weight  per  bushel — 35. 

Weight  per  bushel  is  important  as  a  means  of  estimating 
the  value  of  oats  for  market  and  feeding  as  well,  since  a 
heavy  weight  indicates  that  the  grain  was  well  matured 

76 


JUDGING  OATS  77 

and  the  hull  well  filled  out.  In  the  same  variety,  a  heavy 
oat  usually  has  a  smaller  per  cent  of  hull.  A  good  sample 
of  oats  should  weigh  32  pounds  per  measured  bushel.  Cut 
four  points  for  each  pound  below  standard  weight. 

2.  Soundness — 20. 

The  sample  should  be  sound,  dry,  bright,  and  free  from 
musty,  smutted,  sprouted,  or  otherwise  damaged  grains. 

3.  Color— 15. 

The  color  of  the  grains  should  be  bright  and  uniform 
for  the  bulk  of  the  sample. 

Cut  one  point  for  each  per  cent  of  discolored  grains  and 
grains  not  uniform  in  color  with  the  bulk  of  the  sample. 

4.  Purity— 10. 

The  sample  should  be  free  from  mixture,  other  grain, 
weed  seeds,  straw,  chaff,  and  any  other  foreign  matter  of  any 
kind. 

Cut  one  point  for  each  per  cent  of  mixture  and  the  same 
for  each  per  cent  of  foreign  matter. 

5.  Per  cent  of  hull — 20. 

A  good  oat  may  have  as  much  as  thirty  per  cent  of 
hull.  Cut  two  points  for  each  per  cent  of  hull  above  this, 
for  each  per  cent  below,  add  one  point  to  the  total  score. 


EXERCISE  32.  THE  TREATMENT  OF  SEED  OATS  FOR 

SMUT 

Equipment:  A  bag  of  seed  oats;  formalin  (forty  per 
cent  solution);  a  clean  sprinkling  can;  a  shovel. 

Method:  Spread  the  oats  to  be  treated  on  a  clean, 
tight  floor.  Make  up  a  solution  which  shall  contain 
formalin  to  the  amount  of  one  pint  to  fifty  gallons  of  water. 
Apply  the  formalin  solution  by  means  of  the  sprinkling 
can,  shoveling  the  oats  over  during  the  appHcation,  in  order 
to  secure  a  complete  wetting  of  the  grains.  Continue  the 
application  until  all  of  the  grains  are  thoroughly  moistened, 
but  not  so  wet  that  they  will  stick  together  when  pressed 
in  the  hand.  Shovel  the  oats  into  a  pile  and  cover  with 
clean  bags  for  a  period  of  three  or  four  hours.  After  the 
removal  of  the  bags  the  grain  should  be  dried  as  rapidly 
as  possible  by  spreading  it  in  a  thin  layer  and  shoveling  it 
over  occasionally.  The  same  treatment  is  effective  in  de- 
stroying the  spores  of  the  stinking  smut  on  seed  wheat. 

The  exercise  may  be  continued  by  seeding  two  plots  side 
by  side,  one  with  the  treated  and  the  other  with  the  untreated 
seed.  After  the  grain  is  ready  to  harvest  determine  by 
count  the  per  cent  of  smutted  heads  in  the  two  plots. 

Discussion:  Smut  spores  adhere  to  the  grain  and,  when 
the  kernel  sprouts,  the  fungus  enters  the  plant,  where  it 
grows  without  becoming  visible  until  the  plant  is  ready  to 
ripen.     At  this  time  the  smut  develops  and  converts  the 

78 


THE  TREATMENT  OF  SEED  OATS  FOR  SMUT      79 

grains  into  a  mass  of  dry,  stinking  powder.  The  yield  of 
wheat  and  oats  is  frequently  very  much  reduced  by  the 
presence  of  this  fungus,  and  in  case  of  wheat  the  grain  may 
be  rendered  unfit  for  flour  because  of  the  offensive  odor.  The 
treatment  of  the  seed  with  the  formalin  solution  is  an  effective 
remedy  against  the  smut  of  oats  and  the  stinking  smut  of 
wheat.  Corn  smut,  however,  has  a  different  life  history 
and  cannot  be  controlled  by  seed  treatment. 

This  fungus  develops  in  the  soil  and  produces  spores 
which  are  carried  by  the  wind.  If  one  of  these  spores  finds 
lodgment  in  a  wound  on  the  stalk  or  ear,  it  develops  and 
forms  a  smut  mass.  In  some  years  the  climatic  conditions 
are  much  more  favorable  for  the  development  of  these  smut 
masses  than  in  other  years.  The  only  remedy  is  to  go 
through  the  field,  cut  off  the  masses  of  smut  and  burn 
them  to  prevent  the  further  production  of  spores. 


EXERCISE   33.     THE   PRODUCTION   OF   OATS   IN   THE 
UNITED    STATES 

Equipment :  Yearbook  of  the  United  States  Department 
of  Agriculture. 

Method:  From  the  Yearbook  obtain  the  figures  for  the 
production  of  oats  in  each  state  in  the  United  States.  Repre- 
sent the  production  on  the  accompanying  blank  map  by  the 


United  States. 


Rest  of  the  World. 


Fig,  31. — United  States  Produces  about  One-fourth  of  the  World's 

Oat  Crop. 

use  of  appropriate  shadings  to  indicate  the  areas  of  large 
production.  Those  States  which  produce  more  than  100 
million  bushels  of  oats  should  be  shaded  black;  those  pro- 
ducing more  than  50  million  but  less  than  100  milhon  a 
lighter  shade;  and  those  producing  less  than  50  million 
bushels  left  unshaded. 

Discussion:     The  world's  production  of  corn  and  wheat 
when  measured  in  pounds  is  greater  than  that  of  oats,  but 

80 


PRODUCTION  OF  OATS  IN  UNITED  STATES        81 


82    FIELD  AND  Lx\BORATORY  STUDIES  OF  CHOPS 

when  measured  in  bushels  the  production  of  oats  exceeds 
that  of  any  other  cereal.  Of  the  total  world's  production 
the  United  States  produces  more  bushels  than  any  other 
country,  while  Russia  occupies  second  place.  In  the  United 
States  oats  rank  second  to  corn  in  number  of  bushels  pro- 
duced, but  in  value  the  oat  crop  is  surpassed  by  corn,  cotton, 
hay,  and  wheat. 

In  1850  New  York,  Pennsylvania  and  Ohio  constituted 
the  center  of  production  for  oats  in  the  United  States 
but  by  ICOO  the  center  of  production  had  moved  westward 
to  Illinois,  Iowa  and  Wisconsin.  Statistics  show  that  in 
those  states  where  there  has  been  a  decrease  in  the  acreage 
devoted  to  oats,  there  has  been  an  increase  in  the  corn 
acreage. 

During  the  past  fifty  years  the  oat  crop  of  the  United 
States  has  about  doubled  in  proportion  to  the  population. 


EXERCISE  34.     EARLY  GROWTH  OF  THE   RYE  PLANT 

Equipment:  For  this  exercise  make  the  same  prepara- 
tion as  described  for  corn. 

Method:     Follow  the  directions  given  in  Exercise  15. 

Discussion :  Almost  forty  per  cent  of  the  rye  produced 
in  the  United  States  is  grown  in  the  three  States — Pennsyl- 
vania, Wisconsin  and  Michigan.  Rye  will  grow  on  rather 
poor  soils  and  for  this  reason  it  is  frequently  seeded  in  the 
fall  to  be  plowed  under  and  used  as  a  green  manure  in  the 
spring.  Very  little  of  the  rye  grown  in  the  United  States  is 
used  for  human  food.  In  Russia  and  other  parts  of  north- 
ern Europe,  however,  rye  bread  is  one  of  the  chief  articles 
of  food. 

Rye  is  a  hardy  plant  and  stands  the  winter  better  than 
wheat.  It  may  be  seeded  in  the  standing  corn  in  September 
or  after  the  corn  is  cut  and  shocked  the  rye  may  be  disked 
in  without  plowing.  In  the  spring  the  rye  may  be  plowed 
down  and  the  land  again  planted  to  corn  or  seeded  to 
some  other  crop  Care  should  be  taken,  however,  to 
plow  the  rye  under  in  the  early  spring  before  it  has  made 
too  rank  growth,  otherwise  it  may  exhaust  the  moisture 
from  the  soil  and  thus  injure  the  crop  which  is  to  follow. 
As  a  cover  crop  for  orchards  it  has  given  good  results. 


83 


EXERCISE  35.  EARLY  GROWTH  OF  THE  BARLEY 
PLANT 

Equipment:     For  this  exercise  make  the  same  prepara- 
tion as  that  described  in  Exercise  15. 


Awn 


Fertile 
Glume 
Empty  Glume 


Fig.  33.— Different  Types  of  Barley.  A,  Two-rowed.  B  and  C,  Three - 
rowed.  D,  Hooded  and  E,  Parts  of  the  Spikelet.  (After  Lyon 
and  Montgomery.) 

Method :     Follow  the  direction  given  for  corn  in  Exer- 
cise 15. 

Discussion:     Russia  is  the  leading  country  in  the  pro- 

84 


EARLY  GROWTH  OF  THE  BARLEY  PLANT        85 

ductioii  of  barley.  In  the  United  States  barley  ranks  ninth 
in  point  of  value.  The  market  grades  of  barley  are  largely 
based  upon  color  and  uniformity  of  germination. 

Two  kinds  are  grown  in  the  United  States — the  two-rowed 
and  the  six-rowed.  A  head  of  the  former  has  the  appearance 
of  having  only  two  rows  of  spikelets  situated  on  opposite 
sides  of  the  stem,  while  the  latter  type  has  three  rows  on 
either  side  of  the  stem.  The  two-rowed  varieties  are  grown 
extensively  in  the  Dakotas,  while  the  six-rowed  type  is 
grown  quite  generally  throughout  the  United  States. 

Spring  seeding  is  practiced  in  the  North,  while  in  the 
Southern  States  and  on  the  Pacific  Coast  the  barley  is 
seeded  in  the  fall.  The  winter  varieties  of  barley  are  not 
so  hardy,  however,  as  the  winter  wheat  varieties. 


EXERCISE  36.     THE  IDENTIFICATION  OF  LEGUME 

SEEDS 

Equipment:  A  supply  of  small  bottles;  samples  of  the 
following  legume  seeds  *:  red  clover,  white  clover,  alsike 
clover,  alfalfa  and  yellow  trefoil;  a  pocket  magnifying  glass. 


Fig.  34. — Diagram  to  be  Used  in  Identifying  Seeds. 

*  If  the  local  seedsman  cannot  supply  you  write  to  your  Agricultural 
College  or  to  the  United  States  Department  of  Agriculture  for  samples. 

86 


THE  IDENTIFICATION  OF  LEGUME  SEEDS        87 

Method :  Supply  each  pupil  with  a  bottle  containing  a 
small  quantity  of  a  mixture  of  the  above  seeds.  The  pupil 
should  empty  the  contents  of  the  bottle  into  the  circle  in 
the  center  of  the  diagram  given  below  and  separate  from  the 
mixture  all  of  the  red  clover  seed,  then  remove  the  alfalfa 
seed  into  a  separate  pile  within  the  proper  circle  and  continue 
until  all  of  the  different  kinds  have  been  separated.  If  weed 
seeds  are  present,  they  should  be  separated  also. 


EXERCISE  37.     PURITY  TEST  FOR  GRASS,  CLOVER,  OR 
ALFALFA    SEED 

Equipment:  Samples  of  seed  from  several  sources  and 
a  hand  lens  or  magnifying  glass. 

Method:  Each  student  should  be  given  two  grams  of 
the  sample,  on  a  sheet  of  white  paper.  With  the  help  of  the 
lens  he  should  separate  the  seed  into  three  piles:    (1)  chaff, 


Fig.  35. — ^Examining  Clover  Seed  for  Impurities  and  the  Presence  of 
Other  Seeds.     (Courtesy  of  Extension  Department.) 


TEST  FOR  GRASS,  CLOVER,  OR  ALFALFA  SEED    89 

dirt,  broken  seed  and  stones;   (2)  weed  seed;    and  (3)  pure 
clover  seed.     Save  the  clover  seed  for  Exercise  41. 

Alfalfa,  timothy,  or  other  small  grain  may  be  substituted 
for  clover  in  this  exercise  if  they  are  more  important  crops 
than  clover  in  the  community.     The  selling  price  of  the  seed 


<5    0 
H  C 

Fig.  36. — Natural  Size  and   Magnified   Seeds  of  A,   White  Clover; 
B,  Alsike  Clover  and  f,  Red  Clover. 

should  be  secured  when  the  samples  are  collected.     Fill  out 
the  following  table: 


Sample  No. 

Weed 

Seed, 

Grams. 

ChafT, 
Dirt,  etc.. 
Grams. 

Pure 

Seed, 

Grams. 

Per  cent 

of  Pure 

Seed. 

Selling 

Price 

per  Bu. 

Cost  per 
Bu.  of 
Pure 
Seed. 

90    FIELD  AND  LARORATORY  STUDIES  OF  CROPS 


> 
o 

O 

o   p 
S   > 

s  ^ 

m 


a> 


TEST  FOR  GRASS,  CLOVER,  OR  ALFALFA  SEED    91 

Which  sample  gives  the  largest  amount  of  pm*e  seed  for 
the  money  invested?  Can  you  identify  any  of  the  weed 
seeds?  Taking  into  consideration  the  quality  and  the  weed 
seeds,  which  sample  should  be  purchased? 

Discussion:  Low-priced  seeds  are  usually  the  most 
expensive  that  can  be  purchased,  because  they  frequently 
show  low  vitality  and  may  be  seriously  contaminated  by  the 
presence  of  troublesome  weed  seed. 


Fig.  38. — A  Good  Magnifying  Glass  for  the  Examination  of  Seeds. 


Before  seed  is  purchased  for  the  farm  a  small  sample 
should  be  secured,  tested  for  vitality,  and  examined  for 
the  weed  seeds.  In  many  States  the  Agricultural  Experi- 
ment Station  will  test  samples  free  of  charge  for  the  farmers 
of  the  State. 

Weed  seeds  may  be  sent  to  the  State  Station  or  to  the 
United  States  Department  of  Agriculture,  Washington, 
D.  C,  for  identification. 


EXERCISE   38.     A   STUDY   OF   WEED   SEEDS 

Equipment:  A  collection  of  weed  seeds  properly  labeled;* 
a  hand  lens. 

Method:  Have  each  member  of  the  class  bring  in  a 
collection  of  at  least  five  weeds.  Learn  the  names  of  these 
weeds  and  study  their  habits  of  growth,  nature  of  their  root 
system  and  the  kind  of  seed  which  they  produce. 

Make  a  very  careful  study  of  the  seeds  so  that  each 
student  will  learn  to  recognize  the  more  common  weed  seeds 
that  are  found  in  grass  and  clover  seed.  Extend  the  exercise 
by  bringing  in  seed  samples  containing  weed  seeds  and  requir- 
ing the  class  to  separate  and  identify  as  many  as  possible  of 
the  seed  present. 

Discussion:  Some  weeds  are  annual  in  their  habits 
of  growth  and  if  prevented  from  producing  seed  will  soon 
disappear  from  the  fields.  Many  of  the  more  troublesome 
weeds,  however,  are  perennial,  and  send  up  new  stems  from 
the  roots  year  after  year.  After  the  name  of  the  weed  has 
been  learned,  its  habits  of  growth  can  be  found  described  in 
any  good  manual  of  botany. 

In  connection  with  this  exercise  the  pupils  should  read  the 
following  Farmers'  Bulletins: 

No.  28.  Weeds  and  How  to  Kill  Them. 

No.  260.  Seed  of  Red  Clover  and  Its  Impurities. 

No.  382.  The  Adulteration  of  Forage  Plant  Seeds. 

*  In  many  States  such  a  collection  may  be  secured  from  the  Ex- 
periment Station. 

92 


A  STUDY  OF  WEED  SEEDS 


93 


No.  428.  Testing  Farm  Seeds  in  the  Home  and  in  the 
Rural  School. 

^fi>  "^  t« 


Red  clover 


Trefoil 


Curled  dock 


Fia.  39. — Some  Weed  Seeds  Frequently  Found  in  Clover  and  Grass 
Seed.    Natural  Size  and  Magnified. 

In  addition  to  the  above  bulletins  the  school  should  be  pro- 
vitled  with  weed  bulletins  from  the  State  Experiment  Station. 


EXERCISE   39.     WEED   DISSEMINATION 

Equipment:     Notebook  and  pencil. 

Method:  Study  at  least  ten  different  kinds  of  weeds 
and  determine  how  they  scatter  their  seeds.  Record  the 
results  in  the  following  table : 


Name  of  Weed. 

Method  of  Dissemination. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

Discussion:  Some  seeds  are  provided  with  wings,  or 
feathery  tufts,  which  make  them  easily  carried  long  dis- 
tances by  the  wind;  others  have  hooks  which  cause  them 
to  become   attached  to  the    clothing  or  to  cattle  and  be 

94 


WEED  DISSEMINATION 


95 


carried  from  place  to  place.     Weed  seeds  are  also  widely 
disseminated  by  birds  and  by  streams. 

The  seeds  of  the  common  milkweed  are  provided  with 


Fig.  40. — Canada  Thistle. 
Stems  as  Well. 


It  spreads  by  Seeds  and  by  Underground 
(Second  Ohio  Weed  Manual.) 


a  tuft  of  hairs  which  cause  them  to  be  carried  along  easily 
by  every  gentle  breeze.  The  common  thistle,  dandelion, 
wild  lettuce,  and  many  others,  have  seeds  which  are  pro- 
vided with  tiny  parachutes  by  the  aid  of  which  they  are 


96       FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

carried  long  distances  by  the  wind.  The  manner  in  which 
the  burrs  of  burdock,  cockle  burrs,  Spanish  needles  and 
beggar  lice  stick  to  the  hair  of  animals  and  to  the  clothing 
of  persons,  is  familiar  to  all.  Many  plants,  such  as  the 
wild  raspberry  and  pokeweed,  have  fleshy  fruits  that  are 
eaten  by  birds  and  the  hard  seeds  pass  through  undigested. 
Many  of  these  seeds  germinate  and  grow  wherever  dropped. 


EXERCISE   40.     A   FIELD    STUDY   OF  WEEDS 

Equipment:    Spade  and  magnifying  glass. 

Method:  During  the  early  fall  season  make  a  trip 
across  the  neighboring  corn  fields  and  secure  a  sample  of 
each  different  weed  that  is  encountered.  Dig  or  pull  the 
weeds  and  see  that  each  specimen  includes  roots,  stems, 
leaves,  and  seed  or  blossom. 

The  small  plants  may  be  pressed  between  the  leaves 
of  a  book  and  mounted  entire  on  pieces  of  cardboard. 
Strips  of  gummed  paper  or  court  plaster  may  be  used  to 
attach  the  specimens  to  the  cardboard.  Specimens  of 
some  of  the  larger  plants  may  be  confined  to  a  section  of 
the  stem,  a  leaf,  and  the  flower  or  seed.  In  the  lower 
right-hand  corner  of  the  cardboard  give  the  common  name, 
the  scientific  name,  and  the  date  when  the  weed  was 
collected.  Doubtful  specimens  should  be  sent  to  the  State 
agricultural  college  or  experiment  station  for  identification. 
These  mounted  specimens  will  furnish  material  for  a  second 
exercise,  at  which  time  a  detailed  study  should  be  made 
of  the  root  systems  and  flowering  parts  with  reference  to 
the  method  by  which  the  plants  are  propagated. 

Discussion:  Weeds  are  one  of  the  most  persistent  and 
costly  annoyances  on  the  farm.  They  injure  the  farmer 
by  reducing  his  crop  yields  and  greatly  increasing  the  labor 
necessary  to  produce  a  crop.  Some  of  the  injurious  effects 
of  weeds  arc  the  following: 

97 


98      FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

(1)  Weeds  rob  the  soil  of  food  materials  that  are  re- 
quired by  other  plants.  While  the  total  amount  of  food 
elements  in  the  soil  is  sufficient  in  amount,  the  quantity 


Fig.  41. — Horse  Sorrel,  the  Presence  of  Which  Indicates  an  Acid  Soil. 
(Second  Ohio  Weed  Manual.) 

which  is  available  at  any  one  time  is  not  sufficient   to 
supply  both  the  crop  and  covering  of  weeds. 

(2)  Weeds   rob   the   soil   of  moisture.     In  dry  seasons, 
when  the  moisture  supply  is  limited,  it  is  easy  to  see  that 


A, FIELD  STUDY  OF  WEEDS  99 

a  crop  of  weeds  will  deprive  the  soil  of  the  moisture  needed 
for  the  useful  plants. 

(3)  Weeds  crowd  the  cultivated  plants  and  deprive 
them  of  sunlight  and  of  space,  both  in  the  air  and  in  the 
soil. 

(4)  Weeds  growing  along  fences  and  ditches  afford  a 
good  place  in  which  troublesome  insects  may  live  over 
the  winter. 

Successful  measures  in  destroying  weeds  are  founded 
upon  a  knowledge  of  the  life  of  the  weed  and  the  manner 
of  its  propagation.  To  avoid  introducing  or  spreading  weeds 
is  always  better  than  destroying  them.  It  is  to  be  remem- 
bered, also,  that  while  some  weeds  may  be  completely 
eradicated,  others  can  only  be  held  in  check  and  subdued. 
While  methods  must  vary  for  different  weeds,  a  few  gen- 
eral principles  are  applicable  to  all.  The  following  methods 
are  effective  in  keeping  weeds  in  check: 

(1)  Prevent  all  weeds  from  going  to  seed  and  the  intro- 
duction of  weed  seeds.  This  will  be  sufficient  to  subdue 
the  annuals  and  biennials.  The  numerous  ways,  both 
natural  and  artificial,  by  which  seeds  may  come  in,  makes 
it  impossible  to  carry  out  fully  the  above  rule,  but  much 
can  be  done  in  this  direction  that  will  prove  helpful. 

(2)  Perennial  weeds  of  all  kinds  must  be  cut  repeatedly 
to  starve  out  the  underground  roots  or  stems,  which  in 
this  class  of  weeds  gives  rise  to  a  new  individual  without 
the  production  of  seeds.  If  the  foliage  of  a  plant  is  con- 
stantly destroyed,  the  death  of  the  plant  is  only  a  matter 
of  time  and  will  be  caused  directly  by  root  starvation. 
Any  breaking  or  cultivating  of  the  soil  in  which   these 


100    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

plants  grow  only  serves  the  purpose  of  scattering  them, 
unless  that  cultivation  is  persistent  enough  to  keep  down 
all  growth  of  foUage.  Salt,  coal  oil,  and  sulphuric  acid 
may  also  be  applied,  but  these  are  expensive,  and  per- 
sistent cutting  will  usually  be  found  to  be  the  cheapest 
and  most  effective  method. 

(3)  Some  weeds  indicate  poor  soil  conditions,  and  the 
remedy  is  to  improve  these  conditions.  For  example,  the 
presence  of  horse  sorrel  indicates  an  acid  condition  of  the 
soil.  An  application  of  lime  will  improve  the  soil  and  cause 
this  weed  to  be  crowded  out  by  more  desirable  plants. 
No  amount  of  cutting  or  cultivating  will  eradicate  it  so 
thoroughly.  Wet  spots  are  usually  covered  with  swamp 
grass  and  sedges.  No  amount  of  cutting  will  destroy  them, 
but  tile  drainage  will  cause  them  to  disappear. 


EXERCISE  41.     GERMINATION  TEST  FOR  CLOVER  OR 
GRASS   SEED 

Equipment:  A  pint  of  clover  or  alfalfa  seed;  two  fiber 
plates;  two  pieces  of  white  blotting  paper  and  a  pair  of 
forceps  for  each  student. 


Fig.  42. — Dinner  Plate  Germinator. 

Method:     Prepare  the  germinator  by  moistening  one 

piece  of  blotting  paper  and  placing  it  in  the  bottom  of  the 

fiber  plate.     Now  count  out  100  sound  seeds  and  place  them 

on  the  moist  blotter.     Moisten  the  second  piece  of  blotter 

and  lay  it  over  the  seed.     Finally,  protect  the  blotters  from 

drying  out  by  covering  them  with  the  second  plate.     Keep 

the  blotters  well  moistened  and  at  a  temperature  of  60°  to 

80°  F. 

101 


102     FIIi;i^D;AND;LABORATORY  STUDIES  OF  CROPS 


Kentucky  Blue  Grass:    Magni- 
fied Seeds  and  Natural  Size. 


Brome  Grass:  Magnified  Seeds 
and  Natural  Size. 


Orchard  Grass:   Magnified  and 
Natural  Size. 


Redtop:  Magnified   Seeds 
and  Natural  Size. 


Timothy:  Magnified  Seeds 
and  Natural  Size. 


Fig.  43. — Seeds  of  Some  of  the  Common  Grasses. 


GERMINATION  TEST  FOR  CLOVER 


103 


At  the  end  of  four  days  count  and  record  the  number  of 
seeds  that  have  sprouted.  Remove  all  of  the  sprouted  seed 
so  that  they  will  not  interfere  with  the  subsequent  countings. 
Examine  and  count  the  sprouted  seeds  every  other  day  for 
(Mght  days. 

The  table  below  may  be  used  to  record  the  results  of  the 
germination  tests  of  alfalfa  and  grass  seeds. 


Name  of 

No.  of  Seeds 
in  Sample. 

Number  of  Seeds  Sprouted 
After 

Total  Per 
Cent 

4  Days. 

6  Days. 

8  Days. 

Sprouted. 

- 

Discussion :  Many  samples  of  clover  and  grass  seeds  are 
low  in  vitality.  It  is  essential,  therefore,  that  a  germina- 
tion test  be  made  before  the  seed  is  planted.  Before  pur- 
chasing, it  is  wise  to  secure  samples  and  test  them  for 
vitality  and  for  purity.  A  poor  stand  of  clover  or  grass 
frequently  results  from  the  purchase  of  seed  of  low  vitality 


EXERCISE   42.     A   FIELD   STUDY   OF   LEGUMES 

Equipment:     Spade;  yardstick. 

Method:  Carefully  dig  up  a  clover  plant  in  the  field, 
noting  the  tiny  nodules  on  the  roots. 

Dig  up  other  legumes  and  observe  their  root  system  and 
the  presence  of  nodules. 

These  nodules  are  the  homes  of  the  bacteria  which  have 
the  power  of  taking  the  nitrogen  from  the  soil  and  making  it 
available  for  the  use  of  the  clover  plant. 

Discussion :  Nitrogen  is  a  very  important  food  for  plants 
and  is  very  expensive  when  purchased  in  a  fertilizer.  Only 
the  legumes  that  have  the  nodules  on  their  roots  are  able 
to  use  this  free  nitrogen  of  the  soil  air.  The  legumes  include 
the  common  clovers,  alfalfa,  soy  beans,  cow  peas,  garden 
peas  and  many  other  plants,  all  of  which  have  a  beneficial 
effect  upon  the  soil. 

In  sections  where  a  legume  has  been  grown  for  many 
years  the  bacteria  which  work  upon  its  roots  may  be  found 
in  abundance  in  the  soil,  but  when  a  legume  is  taken  to  a 
new  locality  for  the  first  time  it  is  frequently  desirable  to 
add  to  the  soil  the  proper  bacteria.  This  process  is  called 
inoculation,  and  may  be  performed  by  means  of  pure  cul- 
tures or  by  the  shipment  of  soil  from  a  locality  where  the 
legume  has  been  growing. 

Roots  showing  the  nodules  may  be  preserved  in  glass 
cans  or  wide-mouthed  bottles  by  the  use  of  a  formalin  solu- 
tion consisting  of  one  tablespoonful  of  formalin  to  each 
quart  of  water. 

Note. — Formalin  (forty  per  cent)  can  be  purchased  at  any  drug 
store.     It  is  a  clear,  colorless  liquid. 

104 


A  FIELD  STUDY  OF  LEGUMES 


106 


Ficj.  44. — Soy  Beans.     The  Plant  to  the  Left  Inocuhited,  tlie  One  to  the 
Right  Uninoculated.     (Courtesy  of  Extension  Department.) 


EXERCISE  43.  A  STUDY  OF  SOY  BEANS 

Equipment:  Samples  of  different  varieties  of  soy  beans, 
including  type  samples,  a  balance  and  a  weight-per-bushel 
tester. 

Method:  Give  each  student  a  half  pint  of  soy  beans 
containing  a  small  admixture  of  two  or  three  other  varieties 
and  some  impurities.  Divide  the  sample  into  two  equal 
parts,  make  an  examination  for  purity  and  condition,  and 
record  the  results  in  the  table,  using  the  type  samples  to  aid 
in  the  identification  of  the  varieties. 


Weight. 


Per  Cent. 


(Soy  beans  of  the  variety  class. 
Soy  beans  of  other  varieties .  . 
Other  seeds 
Foreign  matter 


Condition 


Sound  seeds. 
Broken  seeds , 
Moldy  seeds, , 


Weight  of  100  soy  beans  of  variety  class . 
Weight  per  measured  bushel 


The  same  procedure  may  be  used  in  the  study  of  cow 
peas. 

Discussion:  Soy  beans  are  easily  broken  in  the  threshing 
process,  hence  the  grain  found  on  the  market  usually  has  a 

106 


A  STUDY  OF  SOY  BEANS  107 

great  many  broken  seed.  The  broken  grains  are  not  fit  for 
seed,  therefore,  a  sample  which  contains  a  large  number 
of  broken  seed  has  its  value  for  seeding  purposes  much  re- 
duced. Both  purity  and  condition  should  be  taken  into 
consideration  in  determining  the  value  of  a  given  sample 
for  seed  purpose. 

Some  varieties  of  soy  beans  have  been  given  names 
which  indicate  the  length  of  the  growing  season  required 
for  their  development  and  the  color  of  the  bean.  For 
example  we  have  such  varieties  as  medium  yellow,  medium 
green  and  mammoth  yellow.  When  harvested  for  seed 
the  soy  bean  must  be  cut  before  the  pods  are  dry,  other- 
wise they  shatter  badly  and  a  large  percentage  of  the  beans 
will  be  lost  in  the  handling  before  the  crop  gets  to  the 
thresher. 


EXERCISE   44.     A   STUDY   OF   THE   POTATO 

Equipment:  Fifteen  pounds  of  potatoes  of  various  sizes 
and  shapes  and  if  possible  representing  different  varieties; 
a  paring  knife;  a  balance. 

Method :  Weigh  out  ten  pounds  of  potatoes  and  make  a 
study  of  the  qualities  that  affect  the  value  of  the  individual 
tubers. 


Sample  Number. 

1 

f  Round 

Shape 

Oval 

i 

Flat  oval 

! 

r   T.n.rorp,. 

i 

si^e i  fimTii:::::::::::::::; 

r  Yellowish  white 

I 

Pink 

Color  of  skin . .  ^ 

Russet 

Red                   

1 

Other  colors 

j 

r  Corky 

Texture  of  skin  ^ 

Medium  smooth 

Very  smooth 



Depth  of  eyes .   - 
Condition. 

r  Deep        

Shallow 

\  Clean 

Cracked  or  broken 

Diseased 

108 


A  STUDY  OF  THE  POTATO 


109 


Separate  the  potatoes  into  groups  with  respect  (1)  to 
shape,  (2)  to  size,  (3)  color  of  skin,  (4)  texture  of  skin,  (5) 
depth  of  eyes,  and  (6)  condition,  and  record  the  results  of 
each  separation. 


F'iG.  45. — Tubers  of  Desirable  and  Undesirable  Shape.     The  Potato  at 
the  Bottom  is  of  the  Desired  Shape.     (After  Frazer.) 


Select  from  the  sample  five  large,  five  small,  and  five 
knotty,  rough  potatoes.  Weigh  each  group  separately 
and  after  recording  the  weight,  peel  the  potatoes  in  each 
group.     Weigh  and  record  the  weight  of  peeled  potatoes 


no    FIELD  AND  LABORATOEY  STUDIES  OF  CROPS 


and  from  the  weighings  determine  the  per  cent  loss  in  the 
peehngs. 


Weight  of 

Whole 
Potatoes. 


Weight  of 

Peeled 
Potatoes. 


Weight  of 
Peelings. 


Per  Cent 
of  Waste. 


Large  potatoes. 
Small  potatoes . 
Rough  potatoes , 


Discussion:  The  part  of  the  potato  which  we  eat — the 
tuber — is  an  underground  stem.  Every  tuber  has  a  number 
of  eyes  on  the  surface,  each  of  which  marks  the  location  of  a 
bud.  In  some  varieties  the  eyes  are  shallow  while  in  others 
they  are  quite  deep,  and  in  all  varieties  they  are  more  numer- 
ous toward  the  end  of  the  potato  which  is  attached  to  the 
stolon.  Practically  all  higher  plants  have  some  means  of 
storing  up  food  which  can  be  used  at  a  time  when  they  need 
material  to  start  growth  from  a  dormant  condition.  For  the 
potato  plant,  the  tuber  serves  as  a  storage  organ  for  this 
reserve  food. 


EXERCISE  45.     A  FIELD   STUDY  OF  THE  POTATO 


Equipment:  A  pail;  a  potato  fork  and  a  pair  of  spring 
balances. 

Method;  Dig  ten  hills  of  potatoes.  Count  and  weigh 
the  large,  marketable,  and  the  small  tubers  in  each  hill. 
Record  the  results  in  the  following  table: 


Hill. 

Large  Tubers. 

Small  Tubers. 

Number. 

Weight. 

Number. 

Weight. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

Total 

Note  the  variation  in  the  individual  hills.     Which  hill 
would  be  the  most  desirable  to  save  for  seed?    Would  you 

111 


112    FIELD  AND  LABOKATORY  STUDIES  OF  CROPS 

prefer  large  seed  potatoes  from  a  poor-yielding  hill  or  medium 
tubers  selected  from  good  hills? 

Discussion:  In  the  improvement  of  potatoes,  the  seed 
should  be  selected  from  the  best  hills  rather  than  with 
reference  to  the  individual  tubers.     The  careful  selection  of 


>'-*i3<'*„'^>  ..    »~v 


Fig.  46. — The  Use  of  Scabby  Seed  Potatoes  will  Produce  a  Scabby 
Crop.     Seed  Treatment  will  Prevent  the  Disease. 

potatoes  from  the  best  hills  will  result  in  increased  yields 
and  an  improvement  in  the  quality  of  the  potato.  Many 
growers  believe  that  if  the  same  variety  is  grown  in  the  same 
locality  for  a  long  time  it  will  run  out.  The  better  growers, 
however,  believe  that  good  cultural  methods  and  proper 
care  and  selecting  of  the  seed  will  keep  varieties  in  a  pro- 
ductive condition  for  many  years, 


EXERCISE  46.  TREATMENT  OF  SEED  POTATOES  FOR 

SCAB 

Equipment:  A  supply  of  seed  potatoes,  one  ounce  of 
formalin  (forty  per  cent)  and  a  clean  three-gallon  bucket. 

Method :  Mix  the  ounce  of  formalin  with  two  gallons  of 
water.*  This  will  make  sufficient  solution  to  treat  a  bushel 
of  seed  or  more,  since  the  solution  can  be  used  repeatedly. 
Soak  the  seed  in  this  formalin  solution  for  about  two  hours 
just  before  planting.  A  convenient  method  of  treatment 
consists  in  putting  the  formalin  solution  in  a  barrel  or  tub, 
the  potatoes  in  a  basket  or  bag,  and  immersing  them  in  the 
barrel  or  tub  of  solution. 

Discussion :  The  scab  is  a  fungous  growth  upon  the  sur- 
face of  the  potato  and  greatly  diminishes  the  market  value 
of  the  crop.  When  scabby  potatoes  are  planted,  the  spores 
of  the  disease  are  carried  over  to  the  next  crop  and  the  result 
is  a  large  number  of  undesirable,  scabby  tubers.  Since  this 
disease  is  known  to  live  over  in  the  soil  for  several  years, 
a  change  of  soil  is  sometimes  necessary.  However,  it. is 
not  difficult  to  keep  the  disease  in  check  if  proper  precau- 
tions are  taken  regarding  the  treatment  of  the  seed  and  rota- 
tion of  the  crop. 

*  One  pint  of  corrosive  sublimate  in  thirty  gallons  of  water  will  be 
quite  as  satisfactory  as  the  formalin  solution,  if  the  latter  is  more  con- 
venient to  obtain. 

113 


114    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 


^1 

1^05?^   fl 

nil  -^^^H 

03 
CO  "o 


Oi 


EXERCISE   47.     A    LABORATORY   STUDY   OF   COTTON 

Equipment:  A  sufficient  number  of  bolls  of  cotton  to 
supply  each  student  with  three  different  types.  They  should 
be  picked  at  least  two  weeks  before  they  are  needed.  The 
different  types  of  bolls  may  be  obtained  from  different 
varieties  or  by  taking  bolls  from  the  base,  middle  and  top  of 
the  same  plant. 

Method:  Determine  the  length  of  the  lint  taken  from 
the  middle  portion  of  the  seed  and  record  the  average  of  five 
determinations.  Count  the  number  of  seeds  in  each  lock; 
note  the  color  and  amount  of  fuzz.  Make  counts  and 
weighings  necessary  to  fill  in  the  blanks  in  the  following 
table: 


Average 
Length    of 

Lint 
in  inches. 

No.  of 

Seeds 

per  Lock. 

Color 

Number  of  Bolls 
to  Make  a  Pound. 

Number  of 

Seeds 
per  Pound. 

Sample. 

of  Fuzz. 

Seed 
Cotton. 

Lint 
Cotton. 

1 

Discussion :    The  cotton  fiber  grows  in  large  capsules 
called  bolls.     In  the  large  varieties  50  or  60  bolls  will  make  a 

115 


116    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 


Fig.  48.— The  Cotton  Plant  in  Full  Fruit. 


LABORATORY  STUDY  OF  COTTON  117 

pound  of  cotton,  while  in  some  of  the  small  varieties  100  to 
130  bolls  are  required  to  weigh  a  pound. 

Each  boll  usually  contains  four  lobes  or  cells  which  split 
open  as  the  cotton  ripens,  exposing  the  dark-colored  seeds 
which  are  covered  with  white  fibers.  The  seed  cotton  in 
each  cell  is  called  a  lock  of  cotton,  and  will  have  from  six 
to  ten  seeds.  The  short  staple,  upland  cotton  grown  in 
America  has  lint  varying  in  length  from  |  to  Ij  inches,  while 
the  long  staple  has  fibers  greater  than  1\  inches  in  length. 
The  Sea  Island  cotton  produces  lint  from  IJ  to  2|  inches  in 
length.  In  proportion  to  the  diameter  of  their  fibers,  silk 
has  a  greater  tensile  strength  than  cotton  and  wool  a  less. 
All  of  these  fibers,  however,  have  great  tensile  strength. 
It  is  estimated  that  wool  fiber  must  be  five  miles,  cotton 
fifteen  miles,  and  silk  twenty  miles  long  before  it  will  break 
of  its  own  weight. 


EXERCISE  48.     A  STUDY  OF  COTTON  IN  THE  FIELD 

Equipment:    A  tape  measure  and  a  fine-toothed  comb. 

Method:  The  pupils  may  be  taken  to  the  field  for  this 
exercise  any  time  during  the  harvesting  season,  but  prefer- 
ably at  the  second  picking.  Make  the  observations  and 
measurements  necessary  to  fill  in  the  following  table: 


Distance  apart  of  rows 

Distance  apart  of  plants  in  row .  .  . 

Average  height  of  plants 

Average  width  of  plants 

Average  number  of  bolls  per  plant. 
Average  number  of  seeds  per  lock . 

Seeds  fuzzy  or  naked 

Color  of  the  seed 

Average  length  of  the  lint 

Color  of  the  lint 


Where  does  the  longest  lint  occur? 

Make  a  longitudinal  and  cross-section  drawing  of  a  boll, 
showing  locks  and  seeds. 

Discussion:  Cotton  plants  should  be  thinned  to  one 
plant  in  a  place  and  twelve  to  eighteen  inches  apart.  The 
width  of  rows  may  vary  from  thirty  to  sixty  inches.  The 
narrow  row  with  the  plants  further  apart  in  the  rows  will 
usually  give  a  better  yield  of  cotton,  but  the  narrow  rows  are 
more  expensive  to  cultivate.  Cotton  usually  receives  its 
first  cultivation  when  the  plants  are  four  to  six  inches  high, 

118 


119 


120    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

which  is  two  to  four  weeks  after  the  date  of  planting.  This 
first  operation  consists  in  throwing  a  small  furrow  away  from 
the  row  with  a  one-horse  turning  plow.  The  plants  are 
then  chopped  out  with  a  hoe,  leaving  one  plant  every  twelve 
to  fourteen  inches.     In  the  second  cultivation  the  soil  is 


United  States.  Rest  of  the  World. 

Fig.  50. — Cotton  Crop  of  the  United  States  as  Compared  with  the 
World's  Crop. 

thrown  back  to  the  plants  by  going  twice  around  each  row. 
These  two  operations  should  follow  each  other  in  rapid 
succession,  in  order  to  prevent  an  excessive  loss  of  moisture. 
For  the  remainder  of  the  season  the  cultivation  should  be 
no  deeper  than  is  necessary  to  eradicate-the  weeds. 


EXERCISE   49.     A   STUDY   OF   RICE 

Equipment:  A  supply  of  rice  heads  comprising  two  or 
three  different  varieties  such  as  Honduras,  CaroUna  and 
Japan. 

Method:  Give  each  student  a  head  or  a  few  grains  of 
each  variety  and  require  him  to  fill  in  the  outline  given  below : 


Variety . 


Color  of  hull 

Color  of  cuticle 

Density  of  endosperm 

Endosperm  vitreous  or  white. 
Average  length  of  10  grains. . 
Average  width  of  10  grains .  . 
Average  length  of  10  kernels . 
Average  width  of  10  kernels . 

Weight  of  10  grains 

Weight  of  10  kernels 

Per  cent  of  hull  to  grain 


How  many  grains  on  an  average  head  of  rice? 

How  is  the  rice  grain  prepared  for  table  use? 

Discussion :  The  greater  part  of  the  rice  produced  in  the 
United  States  is  grown  by  the  wet-culture  method.  The 
land  is  flooded  immediately  after  planting  in  order  to  sprout 
the  seed.  As  soon  as  this  is  accomplished  the  water  is  with- 
drawn until  the  plants  have  attained  the  height  of  six  to  ten 
inches,  at  which  time  the  land  is  again  flooded  and  the  water 
retained  until  the  grain  is  in  the  milk  stage,  when  it  is  again 
removed  to  permit  the  grain  to  ripen. 

121 


EXERCISE   50.     PLANNING   THE  HOME   GARDEN 

Equipment:  A  50-foot  tape  and  some  plain  drawing 
paper. 

Method:  Carefully  measure  your  home  garden  and  lay 
it  off  to  scale  on  a  plain  sheet  of  paper.  If  the  garden  is  200 
feet  long  and  100  feet  wide,  it  may  be  laid  off  on  the  scale 
of  1  inch  on  the  paper  for  10  feet,  which  will  make  the 
drawing  10X20  inches.  Every  part  of  the  plan  should  be 
drawn  to  the  same  scale.  Make  a  list  of  the  garden  crops 
which  you  wish  to  grow,  and  calculate  the  area  that  should  be 
devoted  to  each.  Finally,  draw  on  your  outline  a  plan  for 
the  garden,  showing  where  all  of  the  crops  are  to  be  located 
and  the  area  that  is  to  be  devoted  to  each. 

Discussion:  Wherever  it  is  possible,  every  home  should 
have  a  plot  of  ground  set  aside  for  the  growing  of  fresh 
vegetables  and  small  fruits.  For  the  farm  home  the  garden 
should  be  large  enough  to  permit  of  horse  cultivation. 
Here  the  rows  should  be  long  and  wide  apart.  In  the  village 
where  the  space  is  limited  the  rows  may  be  placed  close  to- 
gether and  the  plants  given  hand  cultivation. 

A  knowledge  of  the  seasons  and  habits  of  growth  of  the 
various  vegetables  will  enable  a  gardener  to  take  advantage 
of  two  systems,  known  as  companion  and  succession  cropping. 
These  are  designed  to  economize  space,  labor,  and  plant  food 
and  to  give  an  opportunity  of  producing  a  larger  yield  or  a 
greater  variety  on  a  certain  area. 

122 


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123 


124    FIELD   AND  LABORATORY  STUDIES  OF  CROPS 

Companion  cropping  is  the  growing  of  more  than  one  kind 
of  crop  in  the  same  space  at  the  same  time.  That  is,  two  or 
more  crops  occupy  the  ground  together,  but  their  seasons  for 
full  development  are  of  different  lengths  and  the  earlier- 
maturing  ones  are  up  and  utilized  before  their  slower- 
growing  companions  are  large  enough  to  need  the  space. 
The  first  crop  to  mature  may  be  planted  in  the  same  rows 
with  the  others  or  between  the  rows.  Companion  cropping 
ordinarily  would  not  be  practiced  to  any  great  extent  in  the 
farm  garden.  It  often  requires  an  increased  use  of  the 
smaller  hand  tools  and  more  time  and  attention  must  be 
given  to  details  if  the  system  is  to  be  a  success.  On  the 
farm,  there  is  usually  sufficient  space  for  the  garden,  so  that 
the  grower  can  better  afford  to  use  more  ground  than  to 
obligate  himself  to  spend  more  time  and  labor  there.  In 
limited  areas,  companion  cropping  is  usually  an  advantage- 
ous practice. 

Vegetable  growers  make  use  of  a  large  number  of 
combinations  in  their  work,  a  few  of  the  more  common 
ones  being  as  follows:  Lettuce  and  early  cabbage  grown 
alternately  in  the  row.  The  lettuce  will  be  ready  for  con- 
sumption early,  and  after  its  removal  the  cabbage  has  the 
entire  space.  Radish  seeds  may  be  sown  thinly  in  the  same 
rows  with  onions,  parsnips,  parsley,  salsify,  beets,  kohlrabi, 
turnips,  carrots  and  others. 

Succession  cropping  will  probably  prove  of  more  value  to 
the  farmer  than  companion  cropping.  By  this  system,  the 
ground  is  kept  occupied  by  a  crop  nearly  all  of  the  time. 
When  an  early-maturing  kind  is  removed,  it  is  followed  by 
some  other  vegetable  whose  season  will  permit  its  being 


125 


126    FIELD  AND  LABORATORY  STUDIES  OF  CROPS 

planted  at  that  time.  Successions  allow  of  a  much  greater 
variety  of  produce  being  raised  on  a  given  area  than  would  be 
possible  by  single  planting. 

The  following  are  a  few  suggestions  for  successions: 
Celery  to  be  used  succeeding  radishes,  lettuce,  onions,  tur- 
nips, spinach,  early  potatoes  and  other  early  crops;  turnips 


Fig.  53. — Berry  Boxes  may  be  Used  to  Advantage  for  Starting  Tomato 
or  Other  Plants  Indoors  in  the  Early  Spring. 

after  the  same  vegetables;  beets  following  lettuce,  radishes, 
etc.;  early  sweet  corn  replaced  by  beans,  early  potatoes  by 
late  sweet  corn.  There  is  opportunity  for  making  a  very 
large  number  of  combinations,  but  the  above  are  given 
rnerely  as  examples.  The  home  or  school  garden  can  be 
used  by  the  teacher  as  a  laboratory  for  the  demonstration 
of  the  principles  of  soil  management  and  for  illustrating 
methods  of  plant  propagation. 


PLANNING  THE  HOME  GARDEN       127 

The  pupils  should  be  encouraged  to  do  all  the  work  of 
preparing  the  land  as  well  as  planting  the  seed  and  caring 
for  the  plants.  The  preparation  of  the  soil  can  be  converted 
into  a  lesson  in  soil  physics,  the  teacher  explaining  the  nature 
of  the  soil  as  a  source  of  plant  food,  as  a  mechanical  support 
to  the  plant,  and  as  a  storehouse  and  conveyor  of  water 
and  air.  The  influence  of  tillage  on  the  liberation  of 
plant  food  and  water  content,  the  importance  of  hoeing  or 
cultivating  to  eliminate  competition  by  the  destruction  of 
weeds  and  to  conserve  moisture  by  the  maintenance  of  a 
soil  mulch,  and  the  necessity  of  thinning  the  plants  in  the 
row  in  order  to  reduce  competition  and  increase  the  feeding 
area  of  the  individual  plant,  should  be  clearly  presented. 

The  influence  of  pruning  on  tomatoes  to  lessen  competi- 
tion among  the  branches  and  increase  the  food  supply  to  the 
fruits  retained  should  be  brought  out.  The  plants  them- 
selves offer  material  to  use  as  a  basis  for  discussing  their  life 
processes,  including  germination,  growth,  the  functions  of 
leaves,  stems,  roots,  and  flowers,  and,  finally,  the  storing 
of  material  in  the  finished  product. 


APPENDIX 


TO    OBSERVE   CORN   DAY* 

Equipment:  Enthusiasm  and  the  cooperation  of  the 
pupils  and  their  parents. 

Method :  To  make  this  day  a  success,  not  only  the  chil- 
dren, but  the  parents,  must  be  enlisted.  The  social  element 
in  it  is  very  important.  Every  parent  must  be  so  interested 
that  he  will  feel  he  must  be  present.  Plan  for  an  entire  day 
given  to  the  special  occasion.  If  there  is  anyone  in  the 
vicinity  who  is  an  authority  on  agriculture,  secure  him  as  a 
speaker.  If  this  is  done,  have  two  programs,  one  in  the 
forenoon  for  the  speaker  and  one  in  the  afternoon,  when 
the  children  shall  take  a  prominent  part. 

For  the  children's  program,  plan  to  show  the  results  of 
the  work  done  in  the  study  of  com.  Let  it  include  the  best 
compositions  written  on  the  more  interesting  phases  of  the 
work.  The  History  of  Com,  The  Indian  Corn  Dance,  The 
Importance  of  Com  in  America,  The  Development  of  Break- 
fast Foods,  The  Possibilities  in  a  Corn  Stalk,  How  Six  Ears 
went  to  Market,  The  Story  of  a  Stalk  of  Corn,  Number  of 
Days  of  Work  Needed  for  One  Man  and  a  Team  to  Raise  and 

*  Adapted  from  Fanners'  Bui.  617. 
129 


130    FIELD  AND  LABOEATOEY  STUDIES  OF  CEOPS 

Harvest  an  Acre  of  Corn,  are  suggested  subjects.  The 
history  and  work  of  the  farmers'  institute  may  be  reported 
by  one  of  the  older  pupils.  Another  might  give  an  account 
of  what  the  agricultural  college  is  doing  for  the  State. 

If  sufficient  interest  has  been  aroused,  a  corn-judging 
contest  might  be  held.  For  judging  the  corn  exhibits  pre- 
pared by  the  pupils  secure  some  man  who  has  studied  corn 
judging.  Be  sure  to  make  this  a  feature  of  the  day,  making 
the  announcing  of  the  results  a  part  of  the  program. 

Music  should  not  be  omitted  from  the  program.  Some 
patriotic  music  should  be  included,  as  should  the  State 
song. 

Plan  to  have  dinner  at  the  school,  and  use  every  device 
possible  to  make  it  a  corn  dinner.  There  are  many  ways 
in  which  corn  can  be  prepared  which  will  add  to  the  effective- 
ness of  the  plan.  Souvenirs  of  the  day  should  be  made  by 
the  pupils,  carrying  out  the  corn  idea.  For  a  language 
lesson,  prepare  written  invitations  to  the  patrons  of  the 
school.  Be  sure  to  include  the  local  editor  in  the  list  of 
invitations.  Having  a  report  of  Corn  Day  written  by 
some  of  the  pupils  for  the  local  papers. 

The  decoration  of  the  school  room  should  not  be  neglected. 
Use  some  fine  specimens  of  corn  in  completing  the  decora- 
tions. Grains  of  yellow,  white,  and  red  corn  are  full  of 
possibilities,  as  are  the  stalks.  The  rooms  should  be  decor- 
ated so  as  to  give  joy  and  impress  the  thought  that  the  man 
who  raises  a  good  crop  of  corn  is  engaged  in  an  exalted  work. 
The  following  letter  might  be  sent  to  all  patrons  of  the 
school : 


APPENDIX  131 

Dear  Friend  and  Patron  of  the School 

The  teachers  and  pupils  of School,  have  decided 

to  have,  on   ,  a  ''Corn  and  Other  Products  Day," 

and  we  cordially  invite  your  cooperation  and  attendance.  Bring 
good  samples  of  corn,  fruit,  potatoes,  tomatoes,  poultry,  and  other 
home  or  farm  products  that  you  care  to  exhibit,  and  help  us  to 
make  it  a  day  of  educational  value.  A  special  program,  partici- 
pated in  by  the  pupils  and  others,  will  be  a  feature  of  the  day. 

Please  bear  in  mind  that  this  is  your  school  and  that  your 
cooperation  and  presence  will  be  both  a  help  and  an  inspiration. 
Sincerely  yours, 

,  Teacher. 

Selecting  the  Exhibit  for  Corn  Day.  The  exhibit  from 
one  person  usually  consists  of  five  or  ten  ears  of  corn.  Some- 
times a  ten-ear  exhibit  to  represent  the  entire  local  school  is 
made  up  by  selecting  that  number  of  ears  from  the  best  ones 
brought  in  by  all  the  members  of  the  school. 

One  very  important  thing  to  observe  in  choosing  and 
arranging  such  exhibits  is  the  principle  of  uniformity.  This 
means  that  in  order  to  get  a  high  rating  all  the  ears  in  the 
set  must  look  alike  as  nearly  as  possible.  A  corn  judge  often 
discards  a  set  of  five  to  ten  ears  from  any  further  considera- 
tion simply  because  the  exhibitor  included  among  them  one 
ear  that  was  an  inch  longer  than  the  rest,  or  of  a  different 
shade  in  color,  or  that  has  a  different  number  of  rows  of  ker- 
nels, or  kernels  of  noticeably  different  shape  or  size  than 
those  on  the  rest  of  the  ears.  Sometimes  the  size  of  cob  in 
one  ear  differs  from  all  the  others,  or  one  ear  is  crooked  or 
has  "twisted"  rows  of  kernels,  while  all  the  rest  are  straight. 
Any  of  these  defects  spoil  the  uniformity  of  the  set  and  cause 


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132 


APPENDIX  133 

the  set  to  be  marked  severely.  It  is  better  to  select  ten  ears 
that  are  not  the  very  best,  l)ut  are  o7?'A'e,  than  to  include 
one  ear  that  is  either  much  better  or  much  worse  than  all 
the  rest  in  the  set.  Pick  out  the  best  forty  or  fifty  ears  you 
can  find,  and  then  from  these,  by  careful  measurement  and 
comparison,  select  for  your  exhibit  the  five  or  ten  that  are 
nearest  alike. 


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UNIVERSITY  OF  CALIFORNIA  UBRARY 


